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I have a PNG file on my Windows machine of a proposed logo that someone sketched out in PowerPoint. I am tasked with making a master version in Illustrator, and then saving various copies for web use, Word, etc.

The logo is a uniform red color, with white lettering. Simple enough.

Here's my question: When I open the PNG on my Windows machine (where I have PowerPoint) and also on my Mac (where I have Illustrator), the red shade looks darker on Windows. At first I thought it might be that my crappy Dell monitors weren't calibrated as well as my new MacBook Pro, but when I check the color with the eyedropper tool I get RGB values of (181, 10, 0) on Windows, and (188, 0, 10) on the Mac. Same PNG file, totally different colors.

What could be causing this difference? I'm not well-versed in color management profiles, is that what's tripping this up? And how do I ensure that the final logo looks the same across different devices?

EDIT: Here is a cropped portion of the PNG in question:

enter image description here

  • On Windows with Paint.NET, the uniform color shows up as (181, 10, 0)
  • On Mac OS X with Pixelmator, the uniform color shows up as (188, 0, 10)
  • On Mac OS X with Illustrator CS3, the uniform color shows up as (188, 0, 10)
  • On Mac OS X with Photoshop CS3, the uniform color shows up as (181, 10, 0)

What does it show up as on your computer?

EDIT 2 I created the PNG by taking a screenshot of the logo, with the indention of tracing it in Illustrator, so this is not a problem with PowerPoint exporting badly. The problem is with the colors in the resulting PNG file.

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why don;t you provide a sample of the color as made directly from your authoring software, rather than the potential offender? –  horatio Mar 17 '11 at 14:07
    
Looking at the values you give in edit 1. my guess is that OS is irrelevant, as photoshop and paint.net provided the same value. Photoshop CS3 on Windows: (181,10,0) –  JamesHenare Mar 18 '11 at 1:45
    
The Mac guys have their own rules. –  muntoo Mar 20 '11 at 0:25
    
@muntoo I'm confused as to the relevancy of the link, which explains colour profiles and that MacOS has switched to PC-standard 2.2 gamma. What "rules" are different? –  ghoppe Jul 8 '11 at 18:50

7 Answers 7

PowerPoint is not a proper graphics editing product so I wouldn't expect it to accurately render colors the same way as Adobe Illustrator will.

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It doesn't really have anything to do with PowerPoint. Once I have the PNG, I open it up on Windows in Paint.NET and on my Mac in Pixelmator. When I compare the RGB color of the same file, they give different results. My understanding of PNG is that it should accurately maintain the image, unlike JPEG with is lossy. This isn't some complicated gradient or bezier curve where the interpolation might be left up to the software. –  Henry Jackson Mar 17 '11 at 13:49
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interpolation is ALWAYS left up to the software. In this case, my guess is that paint.net and pixelmator are using different default color profiles. I don't see any way in Paint.net to set nor view the color profile being used. In Pixelmator, it looks like you can view it under FILE >> INFO. The image I'm looking at is set to Generic RGB. Without a defined color profile, software doesn't have a set of rules to render the image consistently. –  DA01 Mar 17 '11 at 14:51
    
has it right. The significant omission in the OP is color profile, and it is the color profile that determines the exact RGB values that will be displayed. No profile means the program used to open the file will use whatever its default is, which won't be consistent program to program or across platforms. That's why we have color profiles in the first place. –  Alan Gilbertson May 19 '11 at 20:28

I would use a 3rd party tool like Color Pix to check the color values.

Also, I do know that older versions of PowerPoint (2003 and earlier) don't always accurately export slides as images. I've noted color issues, placement issues (items "moving" from where they were supposed to be on the canvas), and other little oddities.

You may want to find a better tool for making the PowerPoint -> PNG transition (or recreate it from scratch in Illustrator).

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Yes, it can be a color profile problem. As a test, open it in photoshop, discarding the color profile info (you may need to set a preference to "ask me"), and then save a version.


I tried this and it didn't make a difference. The rendering intent in PS does not alter the eyedropper value.

I get the same values as you do in windows using both a print screen of the image as rendered in the browser, and the original png.

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A bit of a wild way you could try, is to just wipe out gamma, icc and chromaticities text chunks in the internal PNG file header. This can be done with a free tool called TweakPNG. You might want to play with it...

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Since it looks like you're only dealing with one or two colors I would explicitly choose the color values in Photoshop / Illustrator by using process colors - that's why Pantone makes them. So when you create your logo in Illustrator open one of the Pantone swatch libraries and choose your process colors from there. Process colors will work fine on the web as well - most folks aren't going to get out a color calibration tool (or are astute enough to say "hey - it looks like the logo displayed on your screen looks different from mine"); they simply accept the fact that different monitors look "different"

The only other option would be to try and force the same color profile across all your programs, but it sounds like you've already tried that.

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Before I say, "The people you're making this for couldn't see the difference if there lives depended on it".

I offer this: I think you're comparing Apples to Oranges, then trying to ask why things are different. The programs you're comparing are completely different (demographic, intended use), you shouldn't expect a seamless use between them - especially at the level you're examining color. You're also using an OS capture procedure to get your base image. I'd say your results are to be expected - they're pretty good.

enter image description here

I did what you did (screenshot the image above and opened Ps, then Ai - both were (181,10,0)). However, I did not get 181,10,0 in Ai until I chose RGB from the preferred color type from the File Menu. Place vs Open yielded different results as well.

(The color swatches above are in order as you have them in your question).

Comparing RGB values makes them seem that they're very different. Perceptually speaking, not so much.

EDIT:

I just caught one of your comments on @DA01 answer.

PNG retains color, JPEG is lossy...both true. BUT your OS isn't necessarily generating the highest quality/most reliable color file - it's snapping a quickie image for you. Your OS doesn't give you the option of PNG8, PNG24, DPI settings, JPG 80% quality, JPG 100% quality....all of those factor into the overall quality and portability of your file.

The screen capture wasn't built to be an industry-standard color manipulator like Ps, or Ai. When you're using those two programs your color choices become hard coded into the files (very easy to see if you create a spot color in either, then place the image into InDesign).

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+1, well written. Good catch on Open vs. Place in AI. FWIW... GIMP on Ubuntu shows 181,10,0 also. –  Farray Jul 11 '11 at 2:24

I know it's probably too late to solve your problem, but great explanation of issue is here http://hsivonen.iki.fi/png-gamma/ (for future reference...)

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1  
Whilst this may theoretically answer the question, it would be preferable to include the essential parts of the answer here, and provide the link for reference. –  Farray Feb 22 '12 at 0:45

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