Need clarify on resolution for lenticular printing

[prabha karan]

Hello remigi,

I have been following you since i have stared leanrnig about lenticular technique.

I have one doubt.

If I print 2 flip images with resolution of 150dpi. i can clearlty see the interlaced lines.

But if i set 600dpi with 8 images (3d depth images). i cant see the interlacing on photoshop preview. i have to zoom more see the lines. If i print also, i cant see lines through my eyes. but i use macroscopic lens and i found out that lines are there. but i could not align it make 3d depth. Am I did anything wrong?

Please help me to clarify this issue.

Iam using 75dpi non adhesive lenticualr sheet (which is available at the moment in india).

Iam using canon pixma series g1030 inkjet printer.

Iam trying to print on a4 size which is 8.2in x 11.32 in

my optical picth is 75.41

[Giovanni Remigi]

Hi Brabhak, I wrote to you by email today. I cannot have a look at this before the end of next week. Can you please send me some screenshots or photos in the meanwhile, to better explain me the problem?

Regards,

Giovanni

[prabha karan]

Thanks for your reply.

https://1drv.ms/u/s!AoXxaVQPkSVItAEdQY0yKMPxyVaP?e=xcY7Ed

(Here is the link)

I tried to create 3d depth image using depthmap creation tool.

My problem is

I did not get 3d better results. (I use 16 frames.)

Even i use less frames, i have to get some result right. but i did not even get any moving effect.

Big question:

1. How to achive 3d depth like you had in your portfolio. I tried to create 2d grescale depth image and many hacks. Still not getting good result.

I understood that you took more photos of that subject and  collage it. Am i correct?

So how to create 3d depth for posters, characters, my art etc.,? is there a way to do that?

So far, I achieved flip image with help of lentigram 2.0 demo.

On Tue, 8 Sep 2020 at 23:21, prabha karan <prabhak...@gmail.com> wrote:

Thanks for your reply.

first_2.png

I did some parallax effect for this finding dory poster.

I tried with 2 frames. it looks like 2 frames shifting to another. I cant feel the depth in that.

So i tried again with 600PPI.  I cant even see any effect from that lens.

Two possible problems

1. Iam using 75LPi which is challenging to align

2. I did something wrong in interlacing. (I watched russel show and tried this interlacing technique on photoshop cc.)

www.png

This is the interlaced file from photoshop cc which i tried to achieve 3d depth.

So far, I achieved flip image with help of lentigram 2.0 demo.

Big question:

1. How to achive 3d depth like you had in your portfolio. I tried to create 2d grescale depth image and many hacks. Still not getting good result.

I understood that you took more photos of that subject and  collage it. Am i correct?

So how do i create 3d depth for posters, characters, my art etc.,? is there a way to do that?

--
You received this message because you are subscribed to a topic in the Google Groups "Lentigram" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/lentigram/6jiYEZAVOS0/unsubscribe.
To unsubscribe from this group and all its topics, send an email to lentigram+...@googlegroups.com.
To view this discussion on the web, visit https://groups.google.com/d/msgid/lentigram/d6bcaf48-5c13-470e-9d60-bd25486139ean%40googlegroups.com.

--

prabha karan about.me/rprabhakaran

--

prabha karan about.me/rprabhakaran

[Giovanni Remigi]

The reason why it took me so long to answer this question is that it would take quite a lot of time to answer exhaustively. I'll try here to give some major points here.

I loaded the images you gave me into Lentigram and I tried to guess the size of the image based on the name of the interlaced file. I used 75.05LPI for and 600PPI.

I tested your image on a lens with an angle of view of 25deg. I do not think you use such narrow angle, I actually think you use a larger one but I used this one just for an initial estimation.

After that, I went into anaglyph mode and selected the depth measurement tool to estimate the depth of your image. As you can see on the attached file (you need to wear red and cyan glasses) the estimated depth on this lens is just half an inch. If instead I use an angle of view of 49deg, which I assume is your case, the depth goes down to a tenth of an inch. 

In summary, you image has not enough depth for a 3D lenticular image. To create an anaglyph definitely, but not for a lenticular image. You can notice in the screenshot that I selected two images which are almost at the opposite sides of the sequence in order to visualize a decent 3D effect in anaglyph mode, which should not be the case.

There is an additional defect on your image: the most important detail in the picture, the eyes, lie behind the stereoscopic window while they should lie On the stereoscopic window. Even if you had enough parallax on this image, the face of your subject would appear blurred. This is not a problem for a stereo anaglyph but it is not working for lenticular where object appearing far from the stereo window will be blurred out.

I'm not an expert in creating depth maps because I usually takes pictures from different angles. I place the cameras far enough to cover the whole lenticular angle. If my lenticular lens has a viewing angle if a=37deg and I take the pictures at D=2m far away from the subject, I use a multi-stereo base (the distance from the opposite cameras) equal to 2*D*tan(a/2). Read this post for more details on this http://kineticsystem.blogspot.com/2018/01/the-lenticular-medium.html

The number of pictures is OK but it does not have any effect of the depth of the image. The depth is controlled by your image total parallax and by the angle of view of the lens. Having a longer sequence if images is only useful in conjunction with the bokeh effect, to remove discretization artifacts automatically.

I cannot give suggestions on how to create a depth map which is an art in itself, I simply do not do it, but once you have it you definitely need to push it more. One possible tool that you cold use to convert a 2D image  + depth map into a sequence of images is Blender. Please refer to this old post here, especially the last comment: https://creativecow.net/forums/thread/twixtor-and-depth-of-field/

I'm using After Effect an a plugin called Twixtor to obtain a long sequence of images from a shot taken with 5 cameras, but there is still a lot of manual work behind. Twixtor does not give any help with adding depth, it only create additional frames between the frames you already have.

Did you try to use this sequence of images to rule out possible issues with pitch tests or printing? https://com-framedlives.s3-eu-west-1.amazonaws.com/lentigram/images/Tree.zip

Kind Regards,

Giovanni