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save AI patterns with >8bit/channel?

Jun 27, 2012 3:21 AM

Hi All,

I would like to create seamless greyscale patterns in AI CS6 by using typical Vector-Tools, Gradients and Transparency.

Output however needs to be 16Bit/Channel RGB - 256 greys are clearly not enough on the Gradients, they would lead to nasty artifacts

in the intended field of use explanation here

I realize that AI is 8bit and that internal Image-Conversion from Vector clearly was no option.

The underlying question for me is - does AI also internally work with just with 256 shades of grey in its gradients too?

Or was there theoretically a way to pass smoother Vectors over to PS which in contrast to AI can save 16 bit Gradients?

All I tried thus far (importing AI though Clipboard as Shape-Layers/Smart-Objects) yielded unusable results for what I'm after.

 

I heavily doubt that such a workflow is possible, but I thought I should at least ask. Thanks for any input!

 
Replies
  • Currently Being Moderated
    Jun 28, 2012 8:17 AM   in reply to polyxo

    When you move stuff to other apps it ceases to be parametric and at that point any discussion about 8bit vs. 16bit becomes an unproductive theoretical/ academic one. The other apps would have to support such gradients natively rather then resorting to the AI/ PDF engine or pre-rasterized data stored in the file. That being so, you cannot expect to get a different result in PS than in AI, give or take color profile/ color space specific quantization differences. So to cut a long story short: No, you won't be able to get 16bit gradients in any form this way. The best you can hope for is to copy&paste paths to PS shape layers and construct your patterns there.

     

    Mylenium

     
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    Jun 28, 2012 9:22 AM   in reply to polyxo

    He's not an Adobe employee any more than the rest of us.

     
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    Jun 28, 2012 9:24 AM   in reply to polyxo

    Illustrator does not *have* to "work with 8 or 16 bits internally". All it knows is what the start and end values are.

     

    I don't think any of the raster formats you can export can be set to 16 bits, so your only option is to transfer your artwork to software that can.

     

    Even if it's not possible to copy "native art" as 8 bits, you could try a smoothing filter in Photoshop.

     

    One can also turn the issue around: given that you import a reasonably smooth image into the 3D software you link to, it would not be unreasonable to expect that software to automatically enhance smoothness and prevent the visible terrace stepping.

     

    (JET is not an Adobe employee. I imagine Illustrator might have taken a few different turns with the latest versions if he was. :)

     
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    Jun 28, 2012 11:55 AM   in reply to polyxo

    polyxo wrote:

    ...Smoothing always means loss of detail...

    And this is exactly what you want to achieve don't you? The artifacts in the 8 bit displacement were caused from the details of the sharp transition between the shading steps of the 8 bit file.

     

    In the example you gave with the link in your first post the smoothness of the 3D displacement map depends on the blurred black and white image of the number 8  and 16 shown first in that web page not on the checker pattern which is a texture on top of the displacement. You can create any texture pattern in 8 bit in Illustrator and when applied as a texture you will have no problem - it will not affect the displacement map. You need higher bit depth for the displacement map texture itself  and it also must be highly blurred image too as shown on that web page. So, the question in your particular example is how you are going to create that blurred 8 and 16 number in Illustrator? A raster program like Photoshop seems to be much more appropriate for this. You can still type or create the 8 and 16 numbers in Illustrator but you need to open them as 16 bit file and blur them in Photoshop and you will be fine.

     

    In order of this thread to make sense you have to show a particular example of what image you want to use as a displacement map and why you want to make it in Illustrator, otherwise it is just guessing about what's in your mind.

     
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    Jun 29, 2012 6:12 AM   in reply to polyxo

    If it is a practical matter why don't you create a 15 bit document in PS and place the ai file into it?

     

    I think you will find the gradient is smooth which it is if placed in an 8 bit as well.

     

    I think you will be able to visually judge by your screen and a proof. That way you will know whether it is a smooth gradient.

     

    And yes I know that does not answer your question even though it actually does if it is actually a practical matter.

     

    The answer is it doesn't matter what happens under the hood if it gets you where you have to be,

     
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    Jun 29, 2012 6:30 AM   in reply to polyxo

    polyxo wrote:

     

    And this is exactly what you want to achieve don't you?

    No. Not at all.

    In that particular case as only some sort of blob is required indeed some smoothing would do the job...

    If you have a very hard edge, first it will never work well in a displacement map especially if you zoom in it because you will see the pixels forming hard edge polygons, and second the 16 vs 8 bit looses advantage because you don't have a transition that creates a smooth 3D displacement surface. For example if you have a grayscale image with bands of different gray steps you will create a staircase steps object with the displacement map. With a very hard edge it will be the texture's pixel density (size of each pixel on the 3D surface) that becomes most important but this approach is not desirable because first it will never be perfect and second increasing the image resolution just to fix hard edges will increase exponentially the rendering time. Look at your example again http://www.digitalartform.com/assets/8bit_full.jpg there is no terrace artifacts where you have completely black color on the grayscale map outside of the blob of the number 8. The staircase effect at the first transition between complete black and the next gray level has a jagged line that is caused by the size of the pixels of the displacement texture as mapped on the 3D surface. If you don't have any smooth transition between two colors then 16 vs 8 bit will loose its advantage.

    polyxo wrote:

    ...

    Please don't let us get the discussion off track. In CG 16 and even 32 bit displacement are establishished for many years and perfect reasons.

    Also it's quite obvious that this sort of consideration does not play a role in daily work you guys have to do.

    That's cool but don't tell me that the whole 3D Industry does it wrong.

    ...

    No one is questioning the importance of 16 and 32 bit and no one is telling you that the 3D industry does it wrong, where did you see that? Quite the opposite, you do need higher bit depth and I would even recommend 32 float instead of 16 bit because it is just slightly better than 8 bit - it is still integer. However with displacement maps you will loose the advantage of the higher bit depth if you don't have blurred edges to create a smooth transition. It doesn't have to be a blob but even with sharp displacement map you have to have some small amount of blur on the edges which will create a bevel like effect to hide the pixelation if you zoom in on the 3D object.

    Here I made a test creating a 3D displacement from this image in a 3D program:

     

    This was 32 bit exr file and the edges of the letters as you see are completely sharp - click on the image to see full resolution

    TestDisplacementTextSharp.jpg

     

    and this is the rendered result - you can clearly see the artifacts from completely sharp edges on the letters

    TestDisplacement32bit_TextSharp.jpg

     

    This was the same 32 bit exr file but the edges of the letters are blurred a little - click on the image to see full resolution

    TestDisplacementTextBlurred.jpg

     

    and this is the rendered result - the blurred edges (loss of detail) avoids the artifacts and it looks nice

    TestDisplacement32bit_TextBlurred.jpg

     

    and this is a displacement rendering using the the same image with the blurred letters but converted to 8-bit targa file. This made the blob larger because of the gamma difference between linear 32 bit and non linear 8 bit but the point is that you can see the artifacts on the blob caused by the 8 bit but the edges of the letters look better than the sharp edges in 32 bit.

    TestDisplacement8bit_TextBlurred.jpg

     

    polyxo wrote:

    ...

    I asked a very concise question. I did not pester you with workflow details because they would not tell anything to many of you.

    But trust me 16 bit make sense, Vectors as Source make sense. And wysiwyg-tiling makes sense too.

    I would have loved to combine that stuff instead of doing the pattern manually with means of Photoshop.

    ...

    No, you didn't ask a very concise question. It would have been concise if you had posted the grayscale images you intend to use as a displacement texture map. Look again in the grayscale image of the number 8 and 16 from the link in your first post and also look at my grayscale images I posted above and tell me why would you want to create these images in Illustrator? Without showing us a specific image, your question about the relevance of using Illustrator for creating it cannot be concise.

     
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    Jun 29, 2012 6:50 AM   in reply to Wade_Zimmerman

    Wade_Zimmerman wrote:

     

    If it is a practical matter why don't you create a 15 bit document in PS and place the ai file into it?

     

    I think you will find the gradient is smooth ...

    Wade, no, this will not work. If you create a gradient in Illustrator and paste it in a 16 or 32 bit image in Photoshop or open the .AI file as a 16 bit file in Photoshop the gradient will not get smoother than the 8 bit file. You can measure this with the eyedropper in Photoshop when set to measure 16 bit in the Info panel. The jumps between the adjacent shades will be pretty drastic in comparison to a gradient created in Photoshop in 16 or 32 bit document.

     
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    Jun 29, 2012 7:19 AM   in reply to polyxo

    Unfortunately no, you can't create completely in Illustrator grayscale images for smooth displacement. You can still create hard edge patterns in Illustrator but you have to blur their edges in 16 or 32 bit file in Photoshop and also add there any smooth elements.

    Photoshop also has nice seamless pattern texture creation (from the 3D menu > New Tile Painting), have you tried that?

     
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    Jun 29, 2012 7:57 AM   in reply to polyxo

    May be you know it but the Offset from Filters > Others will cut any image so its borders are seamless but you have to take care of the seams that that will be moved inside the image. Not as sophisticated as the Tile Painting but nevertheless will turn any image with seamless boarders that can be used as a pattern.

     
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