Illustrator CS4 Assumes 72dpi for Windows? How to change?

[Jon_Bitpu...@adobeforums.com]

Hello,

One of our designers uses Illustrator to layout some web pages. She exports it to a raster format (JPG) but it's too big. After investigating, we found that Illustrator CS4 assumes a 72DPI screen resolution (72 comes from the evil Steve Jobs and is irrelevant to the PC world), and we cannot find a way to change it to 96dpi (the PC standard) even though it's running on a PC workstation.

The workaround is to save as a 72dpi image, and then tell Photoshop to reset it to a 96dpi image (when importing the image in to Acrobat, it will upscale it to 96--enlarging the image). But we would rather speed up the workflow by telling Illustrator to us 96DPI on its artboards.

Does anyone have a way to tell Illustrator to use 96DPI artboards?

thanks,

JP

[Jacob...@adobeforums.com]

JP,

Tell your Illustrator to:

1. Either Save for Web, setting the Image Size to the desired pixel number(s),
2. Or Export as JPEG, setting the PPI to 96.

[Jon_Bitpu...@adobeforums.com]

Hi Jacob,

Thanks for the response.

Exporting to 96dpi actually upsamples the image by 33.3% (96/72) and adds artifacts. This is because Illustrator is hard coded to 72dpi and exporting any raster file format other than 72dpi automatically resamples the image upon export.

Using the save-for-web route saves the right # of pixels (800x600 this case) but the dpi is 72. This is a problem when importing this in to Acrobat Pro since Acrobat Pro knows the proper Windows dpi to be 96, and attempts to upsample the image to this.

Like I said, the workaround is to manually switch the raster file exported by Illustrator to 96dpi using Photoshop (without resampling), but I was hoping to save the extra step by setting Illustrator right in the first place.

thanks,

JP

[Jacob...@adobeforums.com]

JP,

I was assuming vector artwork. Does your Illustrator work with imported raster images and/or rasterize vector artwork before exporting/saving for web (if rasterizing there is the option of changing the rasterization PPI)?

[Jon_Bitpu...@adobeforums.com]

Hello,

She mostly draws vectors and sometimes places images in to the Illustrator file before exporting the entire thing to a raster image. We can switch the export option to 96dpi instead of the Illustrator default of 72dpi, but doing this creates a physically larger upsampled raster image during the Illustrator export.

thanks,

JP

[Jacob...@adobeforums.com]

What if she scales down the image to 75% right after placing it?

[Jay Jhabrix]

Jon,

For web pages the resolution – 72, 96, 300, even 1000 ppi / dpi – is irrelevant. The web uses pixels. Absolute pixels.

IOW, 300 pixels x 300 pixels will display identically irrespective of what the resolution is.

the dpi / ppi count only comes into play for printed matter – brochures, ads, flyers, posters, etc.

Tell her to just design in pixels.

[Jon_Bitpu...@adobeforums.com]

Hello,

The Illustrator document is set-up as 800x600 pixels and outputs an 800x600 image *at 72 ppi*. Of course, the PPI doesn't matter UNTIL importing this image in to Acrobat at which time Acrobat decides that 72 dpi isn't right and upsamples it to 96dpi.

My beef is not so much with Acrobat, but with Illustrator CS4 which either should know that the Windows world operates at 96 PPI, or should allow the user to specify the PPI of the document (it's currently hard-coded to 72 PPI). This would maintain the WYSIWYG behavior of the creative suite.

I was hoping that another user/programmer knew of a hack to set Illustrator CS4 for Windows to 96PPI.

thanks,

JP

[Jay Jhabrix]

Jon,

There' something wrong with what you're doing... if the image is 800x600 pixels , that's what it is. The ppi has no meaning till you go to print. Meaning, if you need the image to fill a space of 6 inches on the horizontal, for:

1/ Brochures by offset: 300 ppi = 1800 pixels
2/ Flex prints for posters: 100 ppi = 600 pixels
3/ Screen: No ppi. Just the pixels.

Also, if you're outputting for web as you first said, why on earth are you using Acrobat? You should be using a web design editor such as Dreamweaver. If the idea is to make the .PDF file available for viewing on the web, then just save it from AI using the 'Smallest File Size" option in the drop down menu.

To repeat, Illustrator is just out-putting whatever the pixels are... the 96ppi vs 72ppi for screen is meaningless. The monitor will display in pixels.

Maybe (i don't use Acrobat to create documents, i only save as an Acrobat (PDF) from AI), you should set up the page in Accrobat using pixels rather than inches or cms/mms.

However, some suggestions:

1/ Just copy the image from AI and paste into Acrobat
2/ In AI, set the document raster settings to 150 and then *downsample* in Acrobat.

However, i don't quite understand or see where the problem lies. If it's a vector file then ppi has no effect, it'll scale seamlessly. If it's a raster file – an image – then you should be using Photoshop.

Cheers,

JJ

[Jon_Bitpu...@adobeforums.com]

Hi JJ,

Give it a try on a PC: export an 800x600 pixel Illustrator file as a JPG, then import that in to Acrobat Pro (create a PDF based on JPG). It will upsample the JPG upon importing.

To avoid this, I must reset the JPG to 96PPI using Photoshop before importing to Acrobat Pro. Since we're trying to present Illustrator layouts to clients in Acrobat, its a bit more effort to have to bring the graphic in to Photoshop and reset the PPI. (Resampling crisp web layouts causes unsatisfactory image degradation.)

I know it's minor and a very narrow issue, but Illustrator should not assume (without the option to correct) that all documents are 72PPI when other creative suite applications DO care about what the PPI is (namely Acrobat).

thanks,

JP

[Jay Jhabrix]

JP,

As i said, if you have to do it that way then set up your document as a 150 ppi and downsample in Acrobat. That way you won't lose quality...

Moreover, i don't quite see the problem in any case... when exporting to JPEG it gives you the option to select the dpi in a drop down box. Choose Custom and enter what you want...

Cheers,

JJ

[Jon_Bitpu...@adobeforums.com]

Hi JJ,

Please physically do this on your system with your own fingers, and you'll see the problem (I'm running CS4 on Windows Vista x64). On paper it may sound simple, but in practice, there is a problem.

When I choose any custom DPI other than 72 when exporting from Illustrator, it will either upsample (>72) or downsample (<72) the image--injecting artifacts in to the image. Acrobat assumes imported files to be 96dpi (Windows), so there is a contradiction in the design of the Creative Suite software.

Ideally, Adobe would allow the PPI of the Illustrator document to be set to something other than 72 PPI. There is no way to "set up your document" to any PPI setting in Illustrator (one can only set the PPI of the Illustrator raster effects).

thanks,

JP

[Jay Jhabrix]

JP...

I think you're not understanding the basic fundamentals:

1/ Pixels are pixels. An image which is 600 x 400 pixels will display on screen as 600 x 400 pixels, irrespective of the screen resolution. i.e. 72 ppi or 96 ppi.

2/ For print, the actual term is not ppi or dpi but Lines per Inch (LPI/lpi) and the ideal for good quality printing is 150 lpi. However, in the real or unreal, or digital world, this translates as roughly 300ppi. (Commonly, but wrongly referred to as dpi.) There are super quality printing presses that require as much as 180 lpi, which equals approximately 360-400ppi. There are even cases of images required at 450 ppi.

3/ Yes, a 72 ppi image will display as less than 1 inch on a Windows OS screen - if you take a ruler and measure it on screen. But it will still display all 72 pixels.

I have given you the work arounds and told you how to resolve the problems you face. You need to try them out.

I really, don't understand where your problem lies. Right at the beginning you said it was for web. So, forget the inches / cms. Stick to pixels.

If you are looking at upsampling an image, you will always lose quality. If you downsample, you will, as well, but it will look fine for that resolution.

You need to decide if your file is going to be in pixels or inches /cms.

Therefore, if you need an image (like a photograph) at 96 ppi, then use Photoshop or any image creation program to set the 96 ppi size for the inch. You can import that image into Illustrator and it wont eff around with it...

If you're creating vector art and need to export as a jpg, then you have the option – in the export dialogue – to choose a custom setting which can be anything you want.

Last, if none of that works for you, Illustrator offers three native options when creating a new document - to reach these click on Advanced in the dialogue box:

1/ 300 ppi
2/ 150 ppi
3/ 72 ppi

My suggestion was use 150 and then downsample the image at the time of export or once you import it into Acrobat.

But, all this is immaterial, if it's for web / screen, it makes no difference. Except that an image in Mac systems will take up more screen space than an image in Windows. There's no way around that.

JJ

[James_...@adobeforums.com]

Does anyone have a way to tell Illustrator to use 96DPI artboards?

As you already know, you can't. Illustrator's basic unit of measure is a point (1/72 inch). Every other unit of measure is factored from that.

Illustrator calls a zoom that displays one inch of measure in 72 screen pixels 100% zoom. That's why if you set Illustrator's zoom to 100%, do a screen capture, then paste the screen capture into Illustrator, the screen capture image is smaller than the original artwork it depicts.

If you set the current zoom to 133% and then do the same thing, the pasted raster image will match the size of the original. (96/72=1.33)

But I don't know why this is causing you any difficulty in exporting images for use on a web page, based on the workflow you have so poorly described so far.

If you will carfully and thoroughly describe your specific workflow, then an expedient workaround may be suggested. List exactly the simplest step-by-step operations required to replicate the problem you are having, and where. Your language so far is too ambiguous to know what exactly your are doing. That's why this thread has gone nowhere so far, despite its rising to the top for several days now.

One of our designers uses Illustrator to layout some web pages. She exports
it to a raster format (JPG) but it's too big.

She is using Illustrator to "layout some web pages." Is she actually exporting the HTML pages from Illustator, or just images for use in HTML pages generated elsewhere?

Is she exporting the JPEG via the Export dialog, or via Save For Web & Devices?

The Export dialog lets you choose the ppi resolution. If you want a 1" image to be rasterized to 96 pixles and to appear 96 pixels in a web browser, set the export resoltuion to 96ppi. The Save For Web dialog lets you set the size in terms of percentage, or by setting the number of pixels. If your image is too big, set the percentage field to 75% (72/96=.75) If it's too small, set the percentage to 133% (96/72=1.33).

After investigating, we found that Illustrator CS4 assumes a 72DPI screen
resolution (72 comes from the evil Steve Jobs and is irrelevant to the
PC world)

I don't know whether Steve Jobs is evil or not. But Steve Jobs is anything but irrelevant to "the PC world". A Mac is a PC, and for many years, Macs dominated graphics. Steve Jobs is also anything but irrelevant to the Windows-using world. Had it not been for having MacOS to continually mimic, intel-based PCs would probably still be using a command line interface, and programs like Adobe Illustrator might still not exist.

An example of irrelevance is your pointless jab at Steve Jobs re this topic.

...we cannot find a way to change it to 96dpi (the PC standard) even though

it's running on a PC workstation.

You can't find it because it's not there to find. You already know this. You can probably work around it, but only if you clearly explain exactly what you are trying to do.

The workaround is to save as a 72dpi image, and then tell Photoshop to

reset it to a 96dpi image...

What does "reset it" mean? Photoshop's Image Size dialog can either resample or scale. Neither should be necessary for an image destined for the web. What matters is the number of pixels. Set that correctly when you export.

When importing the image in to Acrobat, it will upscale it to 96--enlarging

the image). But we would rather speed up the workflow by telling Illustrator
to us 96DPI on its artboards.

You can't tell Illustrator to "use 96DPI on its artboards" (whatever that means). But you can export a raster image at whatever resolution you want.

Exporting to 96dpi actually upsamples the image by 33.3% (96/72) and adds
artifacts. This is because Illustrator is hard coded to 72dpi and exporting
any raster file format other than 72dpi automatically resamples the image
upon export.

If a raster image on the Artboard is scaled to 72ppi, and you then export the content of the Artboard to a raster image at 96ppi, then yes, of course the image will be upsampled. On the other hand, if you have another raster image scaled to 192ppi on that very same Artboard, it will be downsampled to 96ppi when you do the same export. Raster images on the page can individually exist at any ppi. That would be true if Illustrator's base UOM was points or millimeters, or anything else.

Using the save-for-web route saves the right # of pixels (800x600 this
case) but the dpi is 72. This is a problem when importing this in to Acrobat
Pro since Acrobat Pro knows the proper Windows dpi to be 96, and attempts
to upsample the image to this.

How are you "importing" into Acrobat Pro? File>Open? File>CreatePDF>FromFile? Document>InsertPages>FromFile?

If I export an 800x600 pixel image via Illustrator's SaveForWeb dialog and use any of those three methods to open it in Acrobat, I get an image that measures 800 x600 points according to Acrobat's rulers and contains 800x600 pixels. If I then export it (Advanced>DocumentProcessing>ExportAllImages) from Acrobat, I get an 800x600 JPEG image. I open both the AI exported image and the Acro exported image in Photoshop, and they are identical resolutions.

So I can't discern from your incomplete description what you are doing to cause this resampling you are talking about.

Like I said, the workaround is to manually switch the raster file exported
by Illustrator to 96dpi using Photoshop (without resampling), but I was
hoping to save the extra step by setting Illustrator right in the first
place.

"Switch"? Okay, so you open a JPEG that you exported from AI at 72ppi (even though you could have exported it at 96ppi) in Photoshop, resize it without resamping (in other words, simple downscale it) to
96ppi, and then save it as...? Another JPEG?

And then what are you doing with it? Coding it into a hand-coded HTML document? Are you including height and width tags in your HTML? Are you using Dreamweaver or some other WYSIWYG web editor? Are you using an HTML document generated by Illustrator's SaveForWeb?

Because if I do exactly what you described:

1. Export an 800x600 72ppi JPG from Illustrator's SaveForWeb dialog.

2. Open it in Photoshop and use the ImageSize dialog to scale it to 96ppi.

3. Save it as JPEG.

4. Code both images into a hand-coded HTML page, with no width or height tags.

5. View the HTML page in a web browser.

I get an HTML page with two identically-sized images. This is because both images have the same number of pixels.

She mostly draws vectors and sometimes places images in to the Illustrator
file before exporting the entire thing to a raster image.

But what is the resolution of the raster image(s) as scaled on the Illustrator Artboard? If you want to export a 96ppi JPEG of the whole thing, and don't want whatever raster image(s) she used in the layout to be resampled, make sure those raster images are scaled to 96ppi on the Artboard before exporting.

We can switch the export option to 96dpi instead of the Illustrator default
of 72dpi, but doing this creates a physically larger upsampled raster
image during the Illustrator export.

Larger than what? Larger than exporting the image at 72ppi?

Of course it creates a "physically larger" raster image! You've exported 96 pixels for every linear inch instead of 72 pixels for every linear inch. Do both, code each of them into the same HTML page, and the 72ppi export will be smaller than the 96ppi export because it has fewer pixels. As others have been trying to tell you, for web work, it's the number of pixels in a JPEG that determines its size when viewed in a browser, unless you also code tags to display it at a different scale.

(continues...)

[James_...@adobeforums.com]

(...continued:)

The Illustrator document is set-up as 800x600 pixels and outputs an 800x600
image *at 72 ppi*. Of course, the PPI doesn't matter UNTIL importing this
image in to Acrobat at which time Acrobat decides that 72 dpi isn't right
and upsamples it to 96dpi.

Again, what exactly are you doing with Acrobat? There is no "import" command in my copy of Acrobat Professional 9.

My beef is not so much with Acrobat, but with Illustrator CS4 which either
should know that the Windows world operates at 96 PPI, or should allow
the user to specify the PPI of the document (it's currently hard-coded
to 72 PPI). This would maintain the WYSIWYG behavior of the creative suite.

So you want to be able to reset the base unit of measure that Illustrator uses under the hood? (Good luck with that.) Or do you just want document-specific user-defined ruler scales as most every other drawing program has and as I have been ranting about for years?
Or do you just want Illustrator to call the zoom at which 96 screen pixels are used to show an inch of page measure 100%?

Either way, I don't know how this will help you. If Illustrator's base unit of measure were 96ppi, and you exported the content of your Artboard as a 96ppi JPEG, you'd still get the same thing you get by doing that today--a 96ppi JPEG.

Give it a try on a PC: export an 800x600 pixel Illustrator file as a JPG,
then import that in to Acrobat Pro (create a PDF based on JPG). It will
upsample the JPG upon importing.

As described above, I did that. But I used Acrobat's File>CreatePDF>FromFile. And I used two other methods also. Never did I get a resampled image.

To avoid this, I must reset the JPG to 96PPI using Photoshop before importing
to Acrobat Pro.

Again, where is this "reset" command in Photoshop? Are you resampling the JPEG in Photoshop or not?

Since we're trying to present Illustrator layouts to clients in Acrobat,
its a bit more effort to have to bring the graphic in to Photoshop and
reset the PPI. (Resampling crisp web layouts causes unsatisfactory image
degradation.)

If you want to use Acrobat to present your crisp layout, why don't you just SaveAs PDF from Illustrator? Because it's not rasterized? Okay, SelectAll, Edit>Rasterize, then save the PDF.

I know it's minor and a very narrow issue, but Illustrator should not
assume (without the option to correct) that all documents are 72PPI when
other creative suite applications DO care about what the PPI is (namely
Acrobat).

For what it's worth, if either 72ppi or 96ppi is arbitrary, it's 96, not 72. In the days when monitors were fixed-resolution, MacOS decided upon the use of 72 screen pixels to display a real-world inch, because that corresponded to the print-graphics world dimension of 72 points per inch. Windows, on the other hand, chose to use 96ppi because...?

At any given monitor resolution, the 96ppi convention of Windows displays lessof the page at 100% than does the 72ppi convention. That has long been a MacOS advantage in print graphics work. AI is still primarily a print graphics program.

Please physically do this on your system with your own fingers, and you'll
see the problem (I'm running CS4 on Windows Vista x64). On paper it may
sound simple, but in practice, there is a problem.

I'm using CS3 on Vista Business 64. And I did what you described (and more).

When I choose any custom DPI other than 72 when exporting from Illustrator,
it will either upsample (>72) or downsample (<72) the image--injecting
artifacts in to the image.

"It will either upsample or downsample the image..."? Assuming "it" to be referring to the JPEG exporter and "the image" to be a raster image on the Artboard, of course it does! Illustrator is an object-oriented program. You can have any number of raster images on the Artboard at one time, and each of them can have been scaled to a different ppi. That would be true regardless of what Illustrator's display used as 100% zoom. If Illustrator used 96 screen pixels to represent 1 inch of document measure as you want, any raster image on the Artboard scaled to anything other than 96ppi would still get resampled when you export the Artboard contents as a raster image at 96ppi--just as it does today.

Acrobat assumes imported files to be 96dpi (Windows), so there is a contradiction
in the design of the Creative Suite software.

InDesign (a major component of the CS bundles is also a primarily print-oriented program, and it, too, uses the 1-inch-at-72-screen-pixels-is-100%-zoom convention.

I just did this:

1. Using SnagIt, a screenshot utility, took a screenshot of part of your text in this forum. Saved it to disk as JPEG.

2. Opened it in Acrobat Pro (File>Open). Turned on rulers. The image measures 2.4". Did a prepress flightcheck to see what Acrobat calls the image's resolution. 96ppi.

3. Placed the image as a Link in Illustrator (File>Place). The image measures 2.4". Set the Document Info palette to Objects and Linked Images to see what Illustrator calls the image's resolution. 96ppi.

So the only difference here is that at 100% zoom, Acrobat uses up 96 pixels to display an inch of content, and Illustrator uses 72 pixels to dispay an inch of content. The difference is between the zoom and the rulers of the two programs, not the size or resolution of contained images.

Ideally, Adobe would allow the PPI of the Illustrator document to be set
to something other than 72 PPI. There is no way to "set up your document"
to any PPI setting in Illustrator (one can only set the PPI of the Illustrator
raster effects).

An Illustrator document has no PPI. There is no document-level PPI to set up.

Again, devise a simple set of steps which someone else can unambiguously replicate to see where your problem comes in. Then someone can perhaps see where the zoom/ruler difference between AI and Acrobat is causing you trouble in exporting images for web pages, and perhaps suggest the easiest workaround.

JET

[James_...@adobeforums.com]

JJ,

For print, the actual term is not ppi or dpi but Lines per Inch (LPI/lpi).

??

Halftone ruling has absolutely nothing to do with the subject of this thread. LPI and PPI are entirely different things, not two different terms used in two different disiplines for the same thing.

...the ideal for good quality printing is 150 lpi.

The "ideal" for "good"? 150 lpi is a very common halftone ruling, but it is only "ideal" for particular presses, papers, etc. 150 lpi certainly would not be "ideal" for newsprint. Nor would it be "ideal" for a glitzy tabletop book.

There are super quality printing presses that require as much as 180 lpi,
which equals approximately 360-400ppi.

Such-and-such LPI doesn't "equal" anything. "Super quality" presses don't require 180 lpi or any other halftone ruling. High-res imaging devices and high-fidelity presses are not incapable of imaging and printing course halftone rulings. They can also print text and solid line art, can't they? Solid line art doesn't use any LPI at all.

You need to decide if your file is going to be in pixels or inches /cms.

A raster image is going to "be in pixels" regardless of whether it is measured by inches or centimeters.

use Photoshop or any image creation program to set the 96 ppi size for
the inch. You can import that image into Illustrator and it wont eff around
with it...

So long as the format includes scaling data. If it doesn't, Illustrator will scale it to 72ppi. This often occurs with JPEG files, and results in the issue I mentioned with screenshots taken from and then pasted back into AI.

an image in Mac systems will take up more screen space than an image in
Windows. There's no way around that.

You have that backward. Using 72 screen pixels to render an inch of data uses up less screen area than using 96 screen pixels to render that same inch. That was historically one of the major drawbacks of Windows: In the days of small fixed-res monitors, you couldn't see as much of the page at 100% zoom on Windows. Zooming out was not much help, because the CRTs used on most Windows boxes were lower-res and fuzzier than the Trinitrons that came with Macs.

JET

[Jon_Bitpu...@adobeforums.com]

Hello,

I am very sorry if I have offended anyone or appeared contentious in any way. My reference to Steve Jobs in my first post was intended to be a tongue in cheek reference to the PC/Mac rivalry experienced at my various offices over the years (and in recent TV commercials). I don't know Steve Jobs and have no apathy toward him. Also, please accept my thanks for your time and effort in responding to this thread.

Because we have a work-around, it's not that important that I get an answer, but I was posting it to either see if there was a hack and/or to raise the issue to Adobe.

For academic posterity, I'll write the issue in succinct steps here:

Note: the steps are listed below, but the intent is to send web-layout comps to clients in PDF. We don't want to send the vector form of the layouts (e.g., save Illustrator file as PDF) because the clients could easily zoom-in to these layouts and get a false sense of detail and size of the layout--we want to ensure that they're seeing pixels, and the exact size and detail of the layout as it will appear on the web.

1. Create an 800x600 pixel artboard in Illustrator CS4 for PC
2. Put some artwork in this artboard--preferably include solid-color boxes as typically seen on web pages.
3. Either "save for web" or File|Export this artboard to a raster format (e.g., TIFF, JPG).
4. In Acrobat Pro, use the create-from-file option, and select the raster file created in step 3.

At this instant, Acrobat Pro will create two problems: (a) It will upsample the raster file from step 3 and introduce resampling artifacts very noticeable in the solid color areas of the design. (b) Acrobat will also display (at 100% zoom) the layout larger than it appeared on the Illustrator artboard and larger than it will appear on the web.

My workaround is to open the raster file from step 3 in Photoshop and change the PPI from 72 to 96 without scaling/resampling the image and resaving it. After doing this, Acrobat Pro imports this file fine without resampling, and displays it at the same size (100% zoom) as in Illustrator.

Ideally, in my humble opinion, Adobe would allow the artboards to be set to 96 PPI at the time of their creation.

However, I believe I've spent more time in this thread than all the cumulative future time that we'll spend opening these files in Photoshop to set the PPI from 72 to 96!

Again, thanks for your efforts and please accept my apologies for any offense taken.

thanks,

JP

[Jay Jhabrix]

JET...

Am posting on the web, so please bear with me...

1/ the 150 lpi example was just meant to get the OP to rethink his frame of reference... When i said good quality, i meant the average brochure / magazine, that uses a half-tone screen of 150. Obviously newsprint would be far less... It's so many years and, i can't really remember, but was it a 75 dot screen?

2/ Regarding the interpretation, the usage of dpi and ppi has got confused... so, let's stay with ppi... generally, the lpi is half of the ppi. IOW for a 150 lpi you eed a minimum of 300 ppi.

3/ Sorry, by super quality presses, i meant quality printing... and they use a minimum of 180 lpi.

4/ When i told JP that he has to decide between inches or ppi for his file size, i meant exactly that. If you are rendering, for example, a print for magazine you need a minimum of 300 ppi for your images, for a poster it could be 100 and for a hoarding (billboard) as low as 35. The reason for this statement was he was talking web but getting hung up on the 96 ppi res of Windows vs 72 of Mac.

4a/ Yes, paper, print surfaces, all come into the picture... but didn't want to confuse him further...

5/ "A raster image is going to "be in pixels" regardless of whether it is measured by inches or centimeters"

If you look into this, and my earler posts, you'll see that's exactly what i've been trying to tell him.

6/ "an image in Mac systems will take up more screen space than an image in Windows." Mea culpa... bad expression... and bad math to visualisation... wasn't thinking and had the whole thing flipped. Only excuse is that i've never worked on a Mac.

The fundamental problem, i feel, and what i was trying to correct is that JP doesn't seem to realise that if he's creating files for the web, pixels are what we're talking about and not resolution - 72 /96 /150 /300 / 1000 ppi.

I don't use Acrobat, but my statement of deciding the file size in terms of pixels / inches, etc. was aimed at if, Acrobat had that option when presented with a New File dialogue.

Cheers,

JJ

[James_...@adobeforums.com]

1. Create an 800x600 pixel artboard in Illustrator CS4 for PC 2. Put some
artwork in this artboard--preferably include solid-color boxes as typically
seen on web pages. 3. Either "save for web" or File|Export this artboard
to a raster format (e.g., TIFF, JPG). 4. In Acrobat Pro, use the create-from-file
option, and select the raster file created in step 3.

Jon, you still didn't describe exactly what you are doing. Step 3 does not say what resolution you are exporting your problematic image at.

I will therefore assume you export it at 72 ppi since you are setting your Artboard to specific "pixel" measures.

That's where I think your (and many others') confusion is coming from. You have heard that Illustrator's base unit of measure is 1/72 inch. You are then confusing that fact with Illustrator's [stupid] use of "pixels" as a "unit of measure" on its Artboard rulers.

So you are setting your rulers to "pixels", setting your Artboard to what you think is a certain number of pixels (800 x 600) and then fretting over Illustrator's use of 1/72" as a unit of measure. So you consider exporting your "800 x 600 pixel" document at what you believe to be Windows' screen resolution when viewing web pages: 96 ppi. You think, then, that you are exporting an 800 x 600 pixel image at 96ppi. But you're not. You're exporting an image that measures 800 x 600 points at 96 ppi. 800 points is 11.11 inches. 11.11 inches times 96 is 1066 pixels.

You need to remind yourself first that a pixel is NOT a unit of measure. It's not a unit of measure in any program, because a pixel has no absolute size. A pixel is just a square. A square can be any size.

Therefore, when you set your Artboard to 800 x 600 "pixels", you are in fact setting it to 800 x 600 points (or 11.11 x 8.33 inches), not setting its "resolution" to 800 x 600 pixels.

Second, you need to remember that Illustrator is an object-oriented program. It works with objects. It has no "pixel per inch resolution", because each individual object on the page (if it is a raster object) can have a different PPI. PPI is nothing but a scale factor. So even if you have your rulers set to "pixels", you can still have a 1 inch raster image on the page, which at that size may be 300 ppi (or any other scale). But the stupid rulers will still be telling you that image "measures" 72 "pixels"--which, of course, it doesn't. The image contains 300 columns of pixels across those 72 "pixels" indicated on the rulers. The image measures 72 points, not 72 pixels.

See this page <http://www.illustrationetc.com/AIbuds/800x600WebPage/800x600WebPage_SFWFromAI.html> to view the results of performing your steps.

JET

[Jon_Bitpu...@adobeforums.com]

Hi James,

Thanks for all your efforts--definitely a lot of work.

In step 3, I accepted the default 72 "screen" dpi--otherwise, Illustrator would upscale the image upon export (introducing artifacts).

I didn't realize that Acrobat does not upsample the image when importing the 72dpi raster image (as per your experiments in re-exporting the file from Acrobat). The problem seems to be how Acrobat interprets the scale, thus when 100% appears in the Acrobat zoom setting, it really displays 133.33% of the intended page size (as well as showing the upsampling artifacts).

Given this behavior in Acrobat, I think we'll stick to resetting the DPI of the JPG or TIFF file to 96 before importing in to Acrobat so as not to confuse our clients. (We've already created a Photoshop macro/droplet to do this, so it's a very quick workaround.)

thanks again,

JP

[James_...@adobeforums.com]

Illustrator would upscale the image upon export (introducing artifacts).

Just as Acrobat does not resample the image, Illustrator does not "upscale the image" upon export at a higher PPI. It simply exports a raster image at the PPI you specify.

JET

[Jacob...@adobeforums.com]

Jon,

Would the resetting not correspond to the suggestion in post #5?

[Jon_Bitpu...@adobeforums.com]

@James: Thanks for your efforts. You're absolutely right--Illustrator doesn't upscale the image upon exporting it with a DPI setting higher than 72. However, given the intended layout dimension of 800x600 pixels, the resulting TIFF file would be something larger than 800x600 pixels, and larger than the Illustrator artboard at 100% zoom.

@Jacob: Our designers' workflow is to create the design inside Illustrator, so most of the graphics are Illustrator vector objects and not raster images that have been imported in to Illustrator.

thanks!

JP

[James_...@adobeforums.com]

However, given the intended layout dimension of 800x600 pixels, the resulting
TIFF file would be something larger than 800x600 pixels

And that's what all my ranting in post 18 was about: The layout dimension is not 800 x 600 pixels, becaues pixels are not dimensions. The layout is 800 x 600 points.

If you export a raster image that measures 800 x 600 points at 96 ppi, you don't get an 800 x 600 pixel image, and you should never expect to. But people do expect to because of this silly interface design that pretends that a pixel is a unit of measure in a resolution independent, object oriented vector drawing program.

JET

[Bert Philippus]

becaues pixels are not dimensions

Now look what you've done, Jon, you've got JET typoeing! ;)

[Harron_K....@adobeforums.com]

...you've got JET typoeing!

The foam collecting around his mouth dripped down onto the keyboard, making it slippery.

(Sorry, James... Couldn't resist.)

[James_...@adobeforums.com]

Bert, Harron:

Did I mention that a pixel is not a unit of measure?

JET

[Harron_K....@adobeforums.com]

LOL. Duly noted.

[Jon_Bitpu...@adobeforums.com]

Just to beat the dead horse here, and to split hairs, and to use other random metaphors, and to extend this thread to stimulus-package proportions (can you tell our studio is relatively slow right now?)....

I'm not sure if James was being serious when stating that a pixel is not a unit of measure. If so, then I disagree.

All knowledge is contextual. In the context of physical length, a pixel is meaningless since its own length is undefined. However, in the context of resolution and detail, then a pixel is a unit of measure. Web pages are specified in pixels as well as stock photography, for example.

Perhaps its more precise to say that a pixel is not a unit of length.

I understand the roots of Illustrator's measurements coming from points, but in the context of Adobe programs being used for what they're marketed for these days (web/print/etc.), I think it proper for Illustrator to front a user interface option to deal with pixels.

This is already done in Fireworks, so there's already a solution to draw vector objects to build raster images, but Illustrator is so much better than Fireworks in many ways, so we'd rather use that.

I hope Adobe chooses to implement more raster support in to Illustrator CS5.

thanks,

JP

[James_...@adobeforums.com]

JBP:

If an image contains 10 x 10 pixels, "pixels" is not the unit of measure. "10 x 10" is.

Let me say this one more time:

You set the RULERS (fercryinoutloud, they're rulers--devices for making linear MEASURE) to "Pixels".

There is a 1" square raster image on the page that is scaled to 300 ppi. The Rulers say this image MEASURES 72 Pixels.

What of any value do you take that to mean?

JET

[Jacob...@adobeforums.com]

Over here, football pitch is probably the most commonly used unit of area measures, at least in the media.

[James_...@adobeforums.com]

Yeah. My GPS always tells me the number of colors I have to go before the next turn.

JET

[Jon_Bitpu...@adobeforums.com]

I think there is some context-dropping here.

Points are one of many possible units of measure for *length*.

However, in the web world (and all computer UI applications), all context is specified and *measured* in pixels. Of course the same web page looks larger on some monitors, but there is a very real need for designers to layout in pixels.

Rulers (or more accurately "scales") can measure any constant unit. A linear thermometer has a scale/ruler for temperature. A beaker has a ruler for liquid volume.

While a pixel can have various physical lengths upon rendering, because each pixel will be the same size upon rendering, they can be measured on a scale/ruler.

IF all city blocks were of equal length between point A and B, one could count the # of city blocks as a unit of length. However, in the CONTEXT of determining the # of stop lights needed, the # of city blocks is correct, and the length is mostly irrelevant. *If* all football pitches were of equal length, then they too could be used as a length measurement.

Illustrator CAN and HAS been used as a tool for physical printing where physical length is the most important measurement. But Illustrator is being used along side other layout programs to design web context in which the pixel is more important the the physical length.

If the above analytical approach doesn't clear things up, just consider that all Adobe programs except Illustrator and InDesign measure and process in terms of pixels; and they utilize vector objects freely and accurately in a "pixel world."

All I'm asking for is for Adobe to implement more pixel-friendly user interface tools in future versions for those designers who use it for web work in addition to print work.

Respectfully,

JP

PS. A friend once joked to me that he needed to surf the web at a baseball game because "someone on the internet is wrong." I think I've beat my position here enough that any 3rd party viewer will understand my "point."

[Bert Philippus]

A friend once joked to me that he needed to surf the web at a baseball
game because "someone on the internet is wrong."

Laurentiu is your friend?

[James_...@adobeforums.com]

Why are you debating the obvious?

Points are one of many possible units of measure for *length*.

Do tell. No one in this thread said points were the only units for linear measure.

However, in the web world (and all computer UI applications), all context
is specified and *measured* in pixels.

But programs like Illustrator contain many objects, each of which can have its own number of pixels within any linear measure. Why don't you directly answer a point of argument?

Again: What does it mean to you if a 1"x1" 300ppi raster image on Illustrator's Artboard is said to "measure" 72 pixels by Illustrators RULERS (yes, I know that "scale" is another term for ruler. But RULER is the program's term for it!)

IF all city blocks were of equal length between point A and B, one could
count the # of city blocks as a unit of length. However, in the CONTEXT
of determining the # of stop lights needed, the # of city blocks is correct,
and the length is mostly irrelevant. *If* all football pitches were of
equal length, then they too could be used as a length measurement.

Egads. This is what you call "analytical"?

But all pixels ARE NOT of the same length, because a pixel HAS NO absolute length. Using pixels as if it were an absolute measure when it has, in fact, only a relative measure (pixels PER inch, pixels PER centimenter) is exactly what led to the confusion that caused you to misinterpret the results you were getting when you would, on the one hand, set your Illustrator Artboard to "800 x 600 pixels" and then, on the other hand, wonder why you got more pixels than 800 x 600 when you exported it to a rater format at 96 pixels per inch! You the proceeded to complain that Acrobat was upsampling your image for you!

If the above analytical approach doesn't clear things up, just consider
that all Adobe programs except Illustrator and InDesign measure and process
in terms of pixels; and they utilize vector objects freely and accurately
in a "pixel world."

Your "analytical approach" is just obfuscation in a futile attempt to win an argument. Photoshop uses "rulers" delineated in pixels because it's a raster image editing program in which you can't have multiple images at multiple ppi!. Photoshop displays "100%" when the zoom is one screen pixel per one image pixel. Thus, "100%" in Photoshop gives you a different length "inch" when zoomed to 100% for each image of a different resolution!

It's one of the most fundamental difference between raster and vector programs, and it's why pixel rulers make sense when editing one raster image, but not when measuring a page that can contain any number of raster images at different scales at the same time!

JET

[Iain_M...@adobeforums.com]

Can I just say, as a complete new entrant to this type of thing, that whilst your philosophical rants are most entertaining James, it would be really helpful for users like myself who like Jon, have an issue with the fact that Illustrator incorrectly states that a screen image is 100% because it mis-interprets the ppi of the monitor that we are using if someone just gave us an answer as to how to fix this - without nitpicking terminology and semantics.

For posterity, I am not importing, exporting or otherwise. I create an arboard at, let's say 69mm x 91mm (we're metric here...sorry) and then press Ctrl-1 for actual size and it ain't (for reasons already discussed in this thread). Simple as that. How do I fix it.

PS If this has already been answered in the thread please forgive me - I got lost in the rants before I got to the answer

[James_...@adobeforums.com]

it would be really helpful for users like myself who like Jon, have an
issue with the fact that Illustrator incorrectly states that a screen
image is 100% because it mis-interprets the ppi of the monitor

What do you want to be the definition of 100%?

JET

[Iain_M...@adobeforums.com]

Sorry I should not have used the term 100% - what I intended was 'Actual size' as is clear from the following paragraph.

And, to anticipate the likely question: Actual size I define as actual size which means actual size.

[James_...@adobeforums.com]

The actual size of 96 pixels on whatever monitor you happen to be using, or the actual size of one inch?

JET

[Harron_K....@adobeforums.com]

I have several different monitors on machines on which I work with Illustrator. They all have different dot pitches.

I want Illustrator (and my other graphics programs) to send out little 'bots to measure the dot pitches to give me an actual one inch render when I ask for one inch at 'actual size.'

Moreover, at least one of my monitors is an aging CRT with a curved screen. I want Illustrator to give me one inch as measured over the surface of the curve rather than a linear (shortest distance through space between two points) one inch. That way, when I place a piece of paper over the monitor to trace my artwork, I will have 'actual size.' (I later scan that trace into Photoshop to create a PDF to send to my clients. I can only pray they will not use the 'shrink to fit' option in Reader.)

Is that asking too much?

[James_...@adobeforums.com]

Is that asking for too much?

It might be.

But it's not asking as much as asking for a pixel to be the unit of measure for something called "actual size." ;-)

JET

[Harron_K....@adobeforums.com]

But it's not asking as much as asking for a pixel to be the unit of measure
for something called "actual size."

Exactly... er... rather, inexactly!

[James_...@adobeforums.com]

My house is exactly 6.3 colors tall.

I always walk an exact distance of 3.5 songs in the morning.

And I wish this stinkin' software would display 1000 em units at ACTUAL SIZE!

JET

[skull...@gmail.com]

On Feb 2, 11:45 am, Jon_Bitpusher_P...@adobeforums.com wrote:
> Hello,
>
> I am very sorry if I have offended anyone or appeared contentious in any way. My reference to Steve Jobs in my first post was intended to be a tongue in cheek reference to the PC/Mac rivalry experienced at my various offices over the years (and in recent TV commercials). I don't know Steve Jobs and have no apathy toward him. Also, please accept my thanks for your time and effort in responding to this thread.
>
> Because we have a work-around, it's not that important that I get an answer, but I was posting it to either see if there was a hack and/or to raise the issue to Adobe.
>
> For academic posterity, I'll write the issue in succinct steps here:
>
> Note: the steps are listed below, but the intent is to send web-layout comps to clients in PDF. We don't want to send the vector form of the layouts (e.g., save Illustrator file as PDF) because the clients could easily zoom-in to these layouts and get a false sense of detail and size of the layout--we want to ensure that they're seeing pixels, and the exact size and detail of the layout as it will appear on the web.

>
> 1. Create an 800x600 pixel artboard in Illustrator CS4 for PC
> 2. Put some artwork in this artboard--preferably include solid-color boxes as typically seen on web pages.
> 3. Either "save for web" or File|Export this artboard to a raster format (e.g., TIFF, JPG).
> 4. In Acrobat Pro, use the create-from-file option, and select the raster file created in step 3.
>

> At this instant, Acrobat Pro will create two problems: (a) It will upsample the raster file from step 3 and introduce resampling artifacts very noticeable in the solid color areas of the design. (b) Acrobat will also display (at 100% zoom) the layout larger than it appeared on the Illustrator artboard and larger than it will appear on the web.
>
> My workaround is to open the raster file from step 3 in Photoshop and change the PPI from 72 to 96 without scaling/resampling the image and resaving it. After doing this, Acrobat Pro imports this file fine without resampling, and displays it at the same size (100% zoom) as in Illustrator.
>
> Ideally, in my humble opinion, Adobe would allow the artboards to be set to 96 PPI at the time of their creation.
>
> However, I believe I've spent more time in this thread than all the cumulative future time that we'll spend opening these files in Photoshop to set the PPI from 72 to 96!
>
> Again, thanks for your efforts and please accept my apologies for any offense taken.
>
> thanks,
>
> JP

thank you for the work-around!!
this scaling thing has been driving me crazy for years it seems. i
never could figure out why it acrobat was such crap but now i know
it's all a windows/mac thing. :)

[Iain_M...@adobeforums.com]

The actual size of 1 inch; pixels have absolutely nothing to do with this issue except as an unfortunate byproduct of the fact that screens are made up of them - a fact which seems to have escaped you James.

Harron's 'little bots' are exactly the answer with the exception of the rather facetious CRT comment. These 'little bots' are available to the operating system (assuming that the correct drivers are installed) so the real question is why Adobe does not take advantage of them. And I suspect, although I may be proved wrong, that the answer lies in the fact that Adobe assumes that Illustrator will be used to create screen graphics (at which point James you can rant all you like about pixels, because suddenly they are relevant) and have thrown in an 'actual size' option in the view without actually thinking it will ever be used by someone NOT designing for screen (maybe they put it in because InDesign has one, which incidentally doesn't work any better than Illustrator's does - got any smart unhelpful comments about pixels in InDesign James...maybe I should go to my printer and ask him to print me a pamphlet 100x200 pixels and see what he comes up with).

Jon, I don't know if you're out there still, but if you are and you still care, my research has turned up very little - Adobe appear to universally assume that screens will have a 72ppi resolution and use this to calculate the size that 'actual size' is represented on screen with and presumably exported at too. There doesn't appear to be any way around this that I have found. I guess we will have to continue with our workarounds.

[James_...@adobeforums.com]

This past weekend I bought one of those cute little Acer AspireOne netbooks. It has a 1024x600 pixel screen that measures 8.9 inches diagonally. (Since my detractors in this thread are so convinced that a pixel is properly used as an absolute measure, I wonder why they have to specify the inch-based diagonal measure?)

Now, everyone knows stores will soon be carrying the "other" AspireOne model which also has a 1024 x 600 pixel monitor, but one which measures 10 inches diagonal.

Egads. I can see it now: Embedded profiles for each graphic file to convey between different computers the dot pitch and native resolution of the particular monitor(s) being used on the particular computer on which the file was created--just so people can pretend that a "pixel" has an absolute measure.

Iain, I would ask you the same question that Jon neglected to answer: What does it mean to you when a 300 ppi 1" x 1" raster image "measures" 96 pixels on Illustrator's rulers? (Once again, that principle was the very source of Jon's confusion).

JET

[Harron_K....@adobeforums.com]

These 'little bots' are available to the operating system (assuming that
the correct drivers are installed) so the real question is why Adobe does
not take advantage of them.

Monitors are not controlled via 'drivers' (as we are accustomed to with other devices). Look up the 'driver' info in Device Manager under any monitor you have installed, and all you will see is the generic Microsoft display driver (which is part of the OS).

(There are exceptions, of course. Monitors with non-video features, for example, might have associated drivers. This does not change the basic way in which monitors interact with Windows.)

Rather, monitors are defined by .inf files in Windows. They tell the OS what resolutions, bit depths, refresh rates, etc., are available so that the user is prevented from making settings that are beyond the capabilities of the monitor.

I have yet to see an .inf file that defines physical dot pitch or, alternately, physical screen size -- one of which must be present (in addition to resolution) to calculate "actual size."

Please see MSDN's information on .inf file sections:

<http://msdn.microsoft.com/en-us/library/ms801139.aspx>

Although I guess it would be technically possible to add any desired information about the monitor to its .inf file, taking advantage of that information within an OS or application would assume a very special -- and, to my knowledge, non-existent -- cooperation between monitor manufacturers and developers.

My facetious remarks were aimed at a larger question: Even assuming it were attainable, why is "actual size" on the screen so important?

In my print work, there are so many limitations in my monitor view that I regularly go to the time and expense of printing out a hard copy proof... yes, at "actual size." If we are talking about something like a huge poster or billboard, then "actual size" becomes even less meaningful in terms of anything I can view within my immediate work environment -- on the monitor or via printout -- except in small sections.

For the Web -- the world of pixels -- actual size means even less to me. My "proofing" consists of viewing the work on as many different systems as possible. And I'd do that anyway even if I could somehow reliably attain "actual size" on my monitor... whatever "actual size" might mean in this case.

My silly CRT tracing example is, frankly, the only situation I can think of in which "actual size" would be important. I'm sure there are others, and I anxiously await education.