And another thing: right now, when a Windows colleague and I each save a PNG (both of using Save As) with the same color value in it, then upload it to a website and view both images in the *same browser*, the rendered color values are different! So it is currently a crapshoot if two people want to work on the same site.
This behavior is new in CS4.
right now, when a Windows colleague and I each save a PNG (both of using Save As) with the same color value in it
My first guess is that somewhere, somebody is converting the RGB values to a different colour space. Then again, it depends on your definition of "colour value." A red Pantone 485 will be defined as one set of RGB numbers if you’re using AdobeRGB for your working space, and a completely different set of numbers if you’re using sRGB. If you were properly colour-managed, you and your colleague could match any colour regardless of the colour spaces you both use or profiles the images come with.
What I want is very simple: I want the Photoshop files I am working on and the rendered PNGs in my browser to have the same color values.
That depends on if your browser is colour-managed. If not, it probably displays images straight through your monitor profile. If that is the case, while editing your images in Photoshop, go to View-Proof Setup and select your monitor profile. This will show you what the image will look like in your non-colour-managed web browser. When you open or save, make sure there is no conversion taking place.
If you want to use a colour-managed browser, which will show you the more accurate representation of colour as defined by the colour space that was used, then you best read up on colour management and how to use it properly. Say you have a client providing you photos they want on their website, and they want you to match the red of someone’s shirt to their corporate logo. Setting your colour management policies to "off" means there’s a very good chance you won’t get it right, even if someone is using colour-managed browsers to view the photos. (there really is no such thing as turning colour management "off", as Photoshop MUST assume a colour space for your image)
Also keep in mind that 90% of the wolds monitors are uncalibrated as well.
Thanks for your replies.
However, I have been misunderstood so far.
I’m not talking about color calibration; I recognize that the same color will look different on different displays; this is fine, and expected. Everyone’s monitor is different, most are uncalibrated, and colors will *look* different. Cool.
But what I’m saying is that we have computers set up with the same color management policies, the same working spaces (all Generic), and we do not embed color profiles. However, when we save out files with the *same* colors from two different machines, the results are PNGs with different color values in a browser. Put them next to each other and they don’t match. This cannot be right, and I’m looking for a way to fix it. Once again, this was not an issue in Photoshop CS3.
All I want is the raw RGB values to translate. How else can I get HTML colors to match image backgrounds, etc.?
Once again, I could not possibly care less about perceptual color; all I want is *consistent RGB values* from file to file; I do not want two copies of Photoshop exporting two different color values from the same original source color. And I want any given color value in a web PNG to match the same color value I input as a hex color value on a web page.
Surely there is some way to get around color profiles and color shifts, right?
I only glanced at the discussion because the amount of posts about web color management in this forum is becoming deafening. Try JPG instead of PNG. PNG includes gamma data – – so that adds another layer of complexity to color management. Keep it simple with JPG.
But what I’m saying is that we have computers set up with the same color management policies, the same working spaces (all Generic), and we do not embed color profiles. However, when we save out files with the *same* colors from two different machines, the results are PNGs with different color values in a browser.
That’s not possible. Somewhere, somebody is using different colour spaces or converting, or you’re not on the same page as far as how you are defining a colour.
With respect, I have been using Photoshop extensively since version 4.0. I’m really fairly expert, though of course anyone can always learn something new.
What I do know is this: we have been through everyone’s color profiles multiple times; that is the obvious place to start. They are set to the same Generic working spaces (Generic RGB, Generic CMYK, Generic Gray, Dot Gain 20%). All management policies are set to Off, with prompts for profile mismatches. We have made sure that our documents are set to "Don’t Color Manage This Document." We have checked this multiple times, and are now ready to pull our hair out.
And I assure you that this issue is still occurring. Which is why I’m just about ready to re-install CS3, because it worked with PNGs correctly as long as you used the Save for Web command (without converting to sRGB). I’m sure my employers wouldn’t be happy to think the upgrade price they paid was all for naught…
So, obviously, I may have missed something, which is why I posted to this forum. Other than the steps I’ve mentioned above, can anyone think of anything?
Because telling me this is impossible is just not helpful, sorry…
PNG. For once "Jim Jordan" said something relevant. Has he at last learned to stop provocation? If so, congratulations.
@ Jim Jordan
A-ha! Now, the gamma data, you might be onto something there; I will try to look into this. There must be a difference in how CS3 and CS4 handle PNG gamma data. Hmm. Thank you for that thought.
Unfortunately, we do use PNGs because of their alpha-channel features, so JPEG wouldn’t quite be the solution we’re looking for. But thank you for giving me some food for thought.
Does the problem exist with JPG files (instead of PNG files)?
Narrow down the issues. Take the basic troubleshooting steps.
Again –
what is the bit depth of the files?
Here’s another PNG thread with some links to further info: Jim Jordan, "PNG changing colors using save for web (CS2)" #6, 18 Nov 2008 2:49 pm </webx?14/5>
wrote:
They are set to the same Generic working spaces (Generic RGB, Generic CMYK, Generic Gray, Dot Gain 20%). All management policies are set to Off, with prompts for profile mismatches. We have made sure that our documents are set to "Don’t Color Manage This Document." We have checked this multiple times, and are now ready to pull our hair out.
Generic RGB = monitor RGB in most cases and since you didn’t say that all of the systems were using identical monitors and video cards it’s very likely that’s the root of you’re problem.
Generic is not a working space.
Dave Smith
With respect, Generic RGB seems to be a perfectly valid working space with its own profile, completely separate from Monitor RGB, and seems like it does exactly what I want it topass through raw RGB values. And it seems the whole point of it is to *ignore* different individual monitors, which is what I’m after.
Beside which, I fail to see what video cards have to do with RGB value shifts in *actual files*. For the umpteenth time, I could not possibly care less about perceptual changes from screen to screen!
I mean, really people, is it so hard to read through a post and understand what a person is asking, and then either say "that’s weird, I don’t know" or just ignore a forum post if you don’t know the answer or have anything relevant or *factual* to add?
Thank you, Jim Jordan, for highlighting the PNG gamma issue. I am investigating pngcrush to remove gamma values from PNGs. If anyone has a way to do this in my cutting-edge $1000 image editing tool, please share! Thanks.
Ok, so I was wrong about "Jim Jordan"
