[OT] get the black out of psd?
Kathleen
kat
Michael Brady
On Dec 9, 2011, at 3:13 PM, Kathleen wrote:
> Anybody know how to get 4K (CMYK) out of an RGB psd image without affecting the other colors?
You want to remove the black from an RGB image? Can't do that. What is it you want to accomplish?
Brian Pearce
BRIAN PEARCE
Red Jacket Press, LLC
<http://www.redjacketpress.com>
Kathleen
I'm adjusting skintone, which I want to contain 0% black. Now my selected "average" skin sample contains 4 % black. I can adjust levels to get rid of the black, but that shifts C, Y & M which are the way I want them, as is.
kat
Bevi | PubCom
my 2 favorites.
Adjustment layer for Selective Colors:
-- Select neutrals and reduce the slider for K until you get the % you want.
FYI, shadow areas might have a low amount of K in them.
-- You might need to also select Reds for some fleshtones and adjust the
slider too.
-- If your photo has other neutral and red areas that you don't want to
affect, then make a loose selection around the fleshtone areas to mask them.
Adjustment layer for Curves:
-- Select the K channel in the curves panel.
-- Use the top-most eyedropper to find the point on the curve where you want
the fleshtones to be adjusted.
-- Adjust the point up/down to reduce the K in that area.
You can learn a lot about Photoshop color correction by taking Dan Margulis
classes (www.Ledet.com) or his online classes (www.KelbyTraining.com). Dan
is the world's undisputed guru in this area. I've studied with him for eons
and credit him for teaching me my excellent skills.
You also need to know the best CMYK values for different fleshtones.,
otherwise you might end up with purples and greens!
Here's the basic CMYK recipe for Caucasian fleshtones:
http://jaredheinrichs.com/caucasian-skin-tone-cmyk-recipe.html This recipe
was known inside every prepress shop but it was Dan Margulis who published
the magic formula and made it available to Photoshop users.
Search the web and you'll find other recipes for different ethic groups and
races.
--Bevi Chagnon
-----------------------------------------------------
Bevi Chagnon | be...@pubcom.com
PubCom - Trainers, consultants, designers, and developers
Print | Web | Acrobat | XML | eBooks | Section 508
-----------------------------------------------------
Classes: www.PubCom.com/classes
Publishing Blog: www.pubcom.com/blog
-----------------------------------------------------
*** It's our 30th Year! ***
Stephen Clark
> Sorry, I wasn't clear.
>
> I'm adjusting skintone, which I want to contain 0% black. Now my selected "average" skin sample contains 4 % black. I can adjust levels to get rid of the black, but that shifts C, Y & M which are the way I want them, as is.
One way I know is to set your PSD up with a CMYK output profile that has the black curve set high enough to keep black out of skin-tone values while Proof Setup shows you what your changes in RGB do to a CMYK simulation.
If you can't do that conveniently, you have to adjust your targeted skin tone(s) while in RGB in such a way that the resulting CMY values (using the numbers in the Info box as a guide) have a K value of 0.
I've done edits using Selective Color in this fashion successfully many times but much depends on the complexity of the image.
Otherwise Levels will always affect K-component generation unless you change the working or targeted output CMYK profile.
Kathleen
kat
Kathleen
kat
Michael Brady
On Dec 9, 2011, at 6:56 PM, Kathleen wrote:
> No K in curves of levels as it's an RBG file. I'm using info and eyedropper, determining CYMK %.
Kat, this is a convoluted way to go about it. There is not K in RGB because the RGB model uses additive colors and the CMYK model uses subtractive colors. Sample the skin tone in question with 5% K and remove the K *from a CMYK image.* Then convert the CMY values to RGB and that should get you close.
Don't overlook several important factors:
All colors on screen are RGB. ALL colors, even the CMYK colors, because the monitor is only RGB.
The color rendering will vary from program to program on the same computer and monitor, and will vary from one computer and monitor to another. Also, the perceived color of the image will also be affected by the ambient light in the room with the computer. And then there's the matter of ink on paper...
| | | | | | | | | | | | | | | | | | |
Michael Brady
www.michaelbradydesign.com/Blog/ | mich...@michaelbradydesign.com
www.twitter.com/typehuile | www.linkedin.com/in/typehuile | www.facebook.com/typehuile
"Thinking Like a Designer" at https://www.createspace.com/3462255 or http://snipurl.com/z43se
Kathleen
Select an eyedropper (option click)— average is my pref.
Then click the eyedropper
In the info panel choose the color mode for your selection (lower left in info panel). I prefer CYMK.
Then in a curves adjustment layer I can alter the Y in curves blue or the m in red, which usually the percentages that are off.
kat
> --
> you are subscribed to "InDesign talk" on Google Groups, to post: send email to indesi...@googlegroups.com, to unsubscribe: send email to indesign-tal...@googlegroups.com, for more options visit http://groups.google.com/group/indesign-talk
Kat
McGraphics Design, Inc.
(626) 799-2195
http://www.mcgraphics.us
Evans, Rebecca
wrote:
>The color rendering will vary from program to program on the same
>computer and monitor
And which program should we believe? My color settings are synchronized
across the CS programs but the same file open in Photoshop or Illustrator
and visible when placed in InDesign has a completely different color cast.
Very frustrating.
From the raw CMYK numbers, I guessed that Illustrator was rendering a
background blue more accurately than InDesign. Will find out whether I put
my trust in the right program when the book jackets arrive.
Rebecca
Dick Margulis
>
> And which program should we believe?
Believe your Pantone process coated SWOP swatch book. The printed one.
Now this is a problem if all of the color on your cover is within
images. But if you have graphic elements on the page that are in
specific Pantone CMYK colors, then you can hold those swatches up to
your monitor and get a Pretty Good Idea of what the printed cover will
look like.
And while it helps if you have color-calibrated your monitor (I use the
Pantone huey, which is an affordable alternative), you're still stuck
with the fact that the RGB (additive, transmissive) gamut is different
from the CMYK (subtractive, reflective) gamut. So you can still have
surprises.
Three anecdotes:
1. Long time ago. I was tasked with purchasing shirts for our company
sales people to wear at a tradeshow booth, the idea being to pick colors
that worked with our booth graphics. Picked a peach, a butter yellow,
and a nice French blue from the catalog (the same basic premium catalog
all the premium vendors use, so it's printed in gargantuan quantities
and to very exacting color standards, because everyone would raise holy
hell if it weren't). The sales rep said, "Before you place that order,
let me get you some samples." Samples arrived. Peach was dead on. Yellow
was dead on. Blue was a robin's egg blue that bore no relationship
whatsoever to the picture in the catalog. Blues are a bitch.
2. I took a booth at the Self-Publishing Book Expo in NYC a couple
months ago. I wanted to make a couple of table-top graphics so I'd have
something on my table aside from an assortment of loose books. So I took
the RGB colors I use on my website, converted to CMYK, and did the
posters, which came out fine. The I decided to update my home page and
use one of my posters as a graphic. So I brought it into Photoshop,
converted it back to RGB, and saved it as PNG. In theory, the background
color of the graphic should match the background of the website. And in
Internet Explorer it pretty much does. In Firefox, not so much. On the
same monitor. Go figure. (www.dmargulis.com)
3. Sent a book off to my favorite digital printer (no irony intended; he
normally does a superb job). The book came back with the cover
W-A-A-A-A-Y off. The background was supposed to match the author's
website graphic, with an aubergine background (Pantone DS 171-1-C).
Somehow he had a wrong setting on his RIP that first converted this to
the nearest Pantone spot color (in the system's estimation), and then
reconverted THAT into CMYK, arriving at completely different values and
making a botch of the job. Oops. Corrected for the next print run.
Evans, Rebecca
vector pattern rather than a photograph. If it shifts a little, it's not
the end of the world.
Rebecca
C F Majors
have any of you?
http://www.astutegraphics.com/products/phantasm/index.html
--
Carol Majors / Publications unltd
Raleigh NC
. . . . . . . . . . . .
Kathleen
I'd never have thought, but years ago I did a CYMK job with client's dark blue logo spot simulated in CYMK.
Client wouldn't sign. Printer swore the blue passed. The printer threatened, but the client stood by, "no way." We went to another printer.
kat