Chris,
I did read the thread. Every message. I may not of agreed with everything I read, but I read it. I'm not even talking about the pre-multiplication issue. I can save out an image from my 3D package with AND without the pre-multiplication checkbox checked, and photoshop makes the parts of my image with zero alpha completly transparent and I can not find a way around that without resorting to using another piece of software. It's just that simple.
You say I'm making a mistake. You say I'm wanting to change existing workflows. The upgrade from CS2 to CS3 broke our workflow. We used to be able to open EXRs and have the alpha show up as a sepperate channel and then CS3 broke that. Who's breaking workflows? (off topic, but CS4 broke another of our workflows... We want the File->Automate->PDF Presentation back!!! The PDF maker in Bridge CS4 does not cut it.)
I'm fine if you leave the current EXR import in CS4 as the default beheivor. What I want, and what a lot of other people want, is an option somewhere that changes that beheivor. We relize that it's not per the standard. We know that it violates your
interpretation of how it should be. But can't Photoshop be flexable enough to help out everyone? Can't there be an option burried in the Prefrences, an ini file, a registery flag, something that can allow us users to make Photoshop fit the workflow that WE decide to use, be it "right" or "wrong"?
I did see the mention of the super secret, NDA only work to edit the transparency channel. I think that this is a good thing and I look forward to being able to use it, but if the alpha is zero, and you have not kept any of the RGB information, then it sounds like the transparency editor will only allow us to access the RGB values for transparency values > 0.0. Is this correct?
Ray
----- Original Message -----
From: "Chris Cox" <address@hidden>
To: address@hidden, "openexr-user" <address@hidden>
Sent: Friday, June 5, 2009 4:45:43 PM GMT -08:00 US/Canada Pacific
Subject: Re: [Openexr-user] Photoshop Plugin importing as RGB/16 bit
Ray;
Sigh. It really sounds like you didn’t read the thread. You are repeating a lot of the mistakes that I kept correcting in that thread.
The RGB information is preserved as much as possible. If the file format is premultiplied, we do have to un-multiply it. If the format is not premultiplied, we preserve it exactly as-is. We cannot always preserve premultiplied file formats, or all compressed formats – because the application does not work with premultiplied or compressed data.
There were multiple changes requested in that thread – many of which go against interoperability and standards. As explained, we have to deal with many different types of users and many workflows — standards exist to enable those workflows, and violating standards just hurts everyone involved. If you don’t agree with the standards and want to see the standard changed — talk to the owner of the standard.
We are (as explained in the thread) working on solutions to the underlying problems (not being able to edit the transparency channel, and handling divide by zero when un-multiplying).
Chris
On 6/5/09 4:28 PM, "address@hidden" <address@hidden> wrote:
Chris,
I have read the entire thread about this topic at the Adobe Forum (1). It's sad that Photoshop currently discards RGB data of pixels that have zero opacity. I'm not alone (2,3) in wanting the flexibility in Photoshop to be able to open EXR's/PNG's/etc and have the capability to modify/remove the opacity/transparency of an image. I know for a fact that both EXR files (4,5) and PNG files (6) store RGB data when the A channel is set to zero. I personally think that it is a poor decision on Adobe's part to assume that opacity/transparency channel should be loaded into the transparency value without also providing tools to modify that value. If we had some way to paint the transparency back to 1.0 (much the same way that you can paint a layers mask), then I don't think that this would be an issue at all! In my ideal world, the EXR and PNG plugins would create an RGB layer and load the opacity/transparency data into a layer mask.
As far as my "confusion" between "Alpha Channels" and "Transparency/Opacity Channels", I'm not a software developer. I'm a user of commercial software in a professional animation firm. Every application that I use (7) has the ability to read and/or write RGB information to every pixel of an EXR/PNG image regardless the value of the alpha/transparency channel, EXCEPT Photoshop. The lack of Photoshops ability to also do this makes it a little less useful to me. I find it amazing that in order to edit some of my images in an "image editor" (aka Photoshop), that I must strip the alpha channel using another application. Would it not make since that Photoshop should be able to read and write any supported image format, and have the written file contain the same data as the origonal?
I really appreciate your continued activity on the Adobe Forum. From my expirence with other topics/products, many embattled developers quickly get flustered and quit monitoring threads like that. On the other hand, I'm also amazed that you have a large number of users from major VFX/Animation firms (including a co-author of the EXR docs) asking for a change, and you're steadfastness against them in the name of your interpretation of technical accuracy.
I really hope that Photoshop CS5 contains something that will allow us users to edit images in the manner of our choosing. (no matter how wrong we are)
Thanks!
-Ray
(1) http://forums.adobe.com/thread/369637
(2) http://forums.adobe.com/message/1536084#1536084
(3) http://forums.adobe.com/message/1536077#1536077
(4) http://cvs.savannah.gnu.org/viewvc/OpenEXR-images/ScanLines/PrismsLenses.exr?root=openexr&view=log
(5) http://cvs.savannah.gnu.org/viewvc/OpenEXR-images/ScanLines/CandleGlass.exr?root=openexr&view=log
(6) http://www.nc3d.com/temp/PNG_With_Alpha_Sample.png
(7) 3D Studio Max, Lightwave, SoftImage, VRay, After Effects, Combustion
----- Original Message -----
From: "Chris Cox" <address@hidden>
To: address@hidden, "openexr-user" <address@hidden>
Sent: Friday, June 5, 2009 3:00:55 PM GMT -08:00 US/Canada Pacific
Subject: Re: [Openexr-user] Photoshop Plugin importing as RGB/16 bit
Re: [Openexr-user] Photoshop Plugin importing as RGB/16 bit Again, Photoshop is a straight color application – there is no such thing as color values when the opacity is zero.
PNG is also well defined in it’s behavior – and behaves exactly as the file format specification says it must.
TIFF can support alpha channels (which can contain anything) AND transparency/opacity channels. It sounds like you have these confused.
Chris
On 6/5/09 10:14 AM, "address@hidden" <address@hidden> wrote:
Hi Chris,
Maybe I didn't explain this well enough. There really is a couple of issues here. So to explain further, I have an EXR file rendered out of 3DStudio in a HDR scene. The scene is a landscape with buildings, hills, and a sky. The hills and buildings have an alpha of 1.0, the sky has an alpha of 0.0. The RGB information is not limited to a 0.0 - 1.0 range... there are some color values that go up into the 5.0-8.0 range (for example bright reflections on the windows, and the color of the clouds in the sky).
If I use the default EXR plugin in CS4 it creates an RGB/32 document, but the sky comes in 100% transparent. This is great if I don't need the sky, but there is color data for the sky in the EXR file. The sky is blue and there are white clouds. In After Effects I can alter the way it deals with the alpha, and I have the choice to ignore the alpha if I so choose. In Photoshop there are no options to do this. The EXR plugin is not the only one that does this. The PNG plugin for example also discards all color data where the alpha is 0.0. The TIFF plugin on the other hand puts the alpha information into a sepperate channel. I can then choose to use that alpha however I wish. Sometimes it's nice to have the alpha pre-composited with the RGB data the way the PNG/EXR plugin works, but it would also be nice to have an option somewhere that modifies how Photoshop deals with alpha in an image. I would love an option in the main program settings that globally modified how all image importers dealt with the Alpha.
Now if I use the plugin on the OpenEXR website, it brings up a dialog where I can choose to Un-Premultiply, I can change the Gamma, and I can alter the Exposure. It also places the alpha into a sepperate channel like the way the TIFF plugin works. I can see my sky and I have my alpha in a sepperate channel so that I can do with it what I please. The two problems I have with this plugin is that; 1) It creates an RGB/16 document instead of a RGB/32 which clamps the RGB values and leaves me stuck with the gamma/exposure settings I selected during import, and 2) There is no 64bit version of the plugin.
To recap, the default EXR plugin needs a user control for how it deals with the alpha, and the OpenEXR plugin needs to open the image as a RGB/32 so that it does not clamp the color values.
I hope this posting is more clear.
-Ray
----- Original Message -----
From: "Chris Cox" <address@hidden>
To: address@hidden, address@hidden
Sent: Thursday, June 4, 2009 6:37:24 PM GMT -08:00 US/Canada Pacific
Subject: Re: [Openexr-user] Photoshop Plugin importing as RGB/16 bit
Re: [Openexr-user] Photoshop Plugin importing as RGB/16 bit Ray;
Photoshop is a straight color application, and OpenEXR is defined as being premultiplied. This means that OpenEXR data has to be un-multiplied by the transparency/opacity values to work in Photoshop. To a straight color application, there is no meaning to color values when the opacity is zero. If the opacity is non-zero, then the color values are there - just un-multiplied so they will composite correctly.
Photoshop already handles the EXR “A” channel (defined in the spec as opacity/transparency data) correctly – it opens it as opacity/transparency.
What the Photoshop EXR plugin does not do is give you a way to open the transparency channel as an arbitrary alpha channel, or to open channels other than RGBA.
I’m sorry I don’t have a solution for you, but your post sounded like you were confused about the terminology and what was happening to your data (enough so that I still don’t know what’s not working for you with the Photoshop EXR plugin).
Chris
On 6/4/09 4:23 PM, "address@hidden" <address@hidden> wrote:
I'm working on a project that is rendering 32bit floating bit EXR files out of 3DStudio. I'm then compiling these frames in After Effects in a 32 bit floating point composite and it's all working fine. The problem I'm having is that I also need to composite some scenes in Photoshop CS4, and the default Photoshop EXR plugin is tossing out any data from the image that has a transparent alpha. I found the Photoshop plugin on the OpenEXR website and had hopes that it would do what I needed. Thankfully it knows how to handle the alpha channel properly, but unfortunately the plugin imports the image into a 16bit integer document and any value above 1.0 is clipped. I can't use the exposure adjustment to access the over bright details. Because of these import problems I have to run each image through After Effects and do the exposure processing there, then export an image to Photoshop.
Can the maintainer of the OpenEXR photoshop plugin please recompile a new version that imports images into a 32bit document and maintain the full color range, or provide exposure controls in the plugin? Also, I could use a 64bit version of the plugin for the 64bit version of Photoshop.
Thanks,
Ray Collett
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--==-- Ray Collett --==--
Technical Director; Newlands & Company Inc. www.nc3d.com
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