AuthorTopic: --- Expanding the C64 palette to 32 colors ---  (Read 16932 times)

Offline Tourist

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Re: --- Expanding the C64 palette to 32 colors ---

Reply #20 on: July 19, 2011, 03:18:56 am
If you can not tell the difference between colours 1 and 2 your monitor is set too dark I am afraid.

Not necessarily the case.  The png files that Mathias posted include both an ICC profile and chromaticity data in the header chunks.  Here are the files with that information stripped out, just the raw RGB colors (verified with a hex editor).





If these colors look different than the post above, it is because your browser is interpreting either the color correction profile, or the white point, and adjusting what you see.  If the images look the same then either your browser is ignoring that information or your setup is similar to the one Mathias has.

Yay for software trying to help us.  ("I know the palette says xx, but I'm sure he means yy").  See also test pages
http://www.libpng.org/pub/png/png-gammatest.html
http://www.libpng.org/pub/png/png-colortest.html

Tourist

Offline Ai

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Re: --- Expanding the C64 palette to 32 colors ---

Reply #21 on: July 19, 2011, 03:55:50 am
Let's not forget KittenMaster's side of it: setting his display profile correctly in the first place.
(And Mathias -- choosing the right image color profile)

Desktop color-correction is still young and quirky. Raw RGB values without a profile attached, only have very vague meaning ('something that looks somewhat like sRGB.. maybe if you squint')
If you insist on being pessimistic about your own abilities, consider also being pessimistic about the accuracy of that pessimistic judgement.

Offline Mathias

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Re: --- Expanding the C64 palette to 32 colors ---

Reply #22 on: July 19, 2011, 04:48:35 am
Thanks, Tourist. I see that your stripped-out version loses a very slight bit of saturation compared to mine (load them both up in different browser tabs and toggle back and forth to a quick/easy comparison). Virtually no difference really. But, I don't understand why they are different. I get that the ICC instructs the computer/program "how" to interpret RGB values, but honestly, beyond that the science of it all just doesn't jive for me . . .


AI, I use the same color profile for all my RGB Photoshop projects - the one that came with my dual monitors: "Samsung - Natural Color Pro 1.0 ICM". It makes everything look correct in my Photoshop. I realize that browsers pretty much all use sRGB, but my images usually translate quite well once saved from PS and displayed in a browser, such as when I host 'em somewhere and link them in a forum.
« Last Edit: July 19, 2011, 02:53:25 pm by Mathias »

Offline Ai

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Re: --- Expanding the C64 palette to 32 colors ---

Reply #23 on: July 19, 2011, 05:29:46 am
I get that the ICC instructs the computer/program "how" to interpret RGB values, but honestly, beyond that the science of it all just doesn't jive for me . .
Okay, Color management 101:
* All color management depends on having TWO color profiles. One is for the image data. The other is for the display. We could call these 'source' and 'target'
* That combination of two profiles allows the computer to calculation the relation between them, and transform the data using that, so that it displays as intended. To be more explicit: the actual displayed RGB values change, to match the original appearance of that color.
* The above is an ideal scenario. Most commonly, people don't have color management setup (in which case, the browser assumes sRGB as a target.. hopefully. Some just don't color manage at all.). Fairly commonly, artists don't have color profiles setup; or they have assigned their display profile as the image profile (this seems to be what you did), which effectively disguises that their settings are exactly the opposite to what they should be.
* As a rule the image profile (commonly known as 'working space') should be something standard (if you can use sRGB, do so; otherwise, there are Various other working spaces, kindly catalogued by Bruce Lindbloom)
* The display profile should accurately describe the color characteristics of your monitor. Some professionals use colorimetry devices to recalibrate their display profiles every 1-2 months. It's generally a good practice to assume the viewer is running uncalibrated sRGB (and so, make sure your image is converted to sRGB -- the best you can do overall -- when you are exporting a file to show on the web)

Charles Poynton accurately describes the details, wherefores, howtos, etc in his Color FAQ
« Last Edit: July 19, 2011, 07:35:55 am by Ai »
If you insist on being pessimistic about your own abilities, consider also being pessimistic about the accuracy of that pessimistic judgement.

Offline HughSpectrum

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Re: --- Expanding the C64 palette to 32 colors ---

Reply #24 on: July 19, 2011, 06:17:53 am
I just used Windows 7 to configure my monitor in conjunction with a monitor calibrating site.

Tourist's image does indeed appear slightly lighter, and colors 1 & 2 are more distinguishable.

Offline Mathias

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Re: --- Expanding the C64 palette to 32 colors ---

Reply #25 on: July 19, 2011, 03:36:48 pm
oh god . . . I'm going to die in this color management hell . . . leave me AI, just leave me . . . there's no hope for me . . . go . . . JUST GO!!!14

Gaaaaahhhhhhh arrrr . . . why  . . .



I will try and read that color FAQ PDF. In the digital realm, I feel like an alien from War of the Worlds; the mere basic nature of the environment itself is hostile towards me and if not careful, deadly. Time to get my color legs. Thank you for being you.

Offline Tourist

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Re: --- Expanding the C64 palette to 32 colors ---

Reply #26 on: July 19, 2011, 08:27:00 pm
Ai : I agree, although I would use stronger language than 'quirky.'   :) 

When folks talk about png images being too light or dark, the culprit is usually an embedded gamma correction chunk.  Since these files didn't have one, I agree the problem is likely KittenMaster's setup.

Mathias:  Eh, don't worry so much.  You're not calibrating an input device like a camera or scanner, so just use sRGB for your pixels.  Calibrate your monitor.  Done. 

When I look at your colors, I see too many light pinks (29, 30, 31), too many blue shades (middle row), and probably too many dark colors (first column, and #2) for my tastes.  But I don't have a different methodology to offer.

Tourist

Offline Ai

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Re: --- Expanding the C64 palette to 32 colors ---

Reply #27 on: July 20, 2011, 12:33:35 am
Tourist: I don't think you agree with me. Specifically, I think KittenMaster's setup is probably okay. I believe that Mathias is not using sRGB for his pixels.

Mathias: If I've understood the situation correctly, at least for pixel art, you need to use the sRGB profile for your image, and that Samsung profile for your display (rather than your current situation, which seems to be approximately the reverse -- Samsung on the image, sRGB assumed as default for your display). Last thing I heard, the default image profile ('working space') was in the preferences, for Photoshop (http://www.computer-darkroom.com/ps10_colour/ps10_1.htm). The display profile is something you set system-wide. It's possible you have a Samsung utility to do this -- I don't know how that works on Windows.

If you do prints, it's also important to get this handled.  A lot of printers expect sRGB, and depending on how well your color management is setup, sending non-sRGB data can result in outputs that are simply wrong.
If you insist on being pessimistic about your own abilities, consider also being pessimistic about the accuracy of that pessimistic judgement.

Offline DawnBringer

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Re: --- Expanding the C64 palette to 32 colors ---

Reply #28 on: July 21, 2011, 11:59:46 am
Interesting stuff. This is the result produced by my "Expand Palette" Grafx2-script (It comes with the program...but this was produced with an updated/improved algorithm I think).
It "Continously fill the greatest void in the area of the color-cube enclosed by (or along ramps of) initial colors. This algorithm will create lines of allowed colors (all ranges) in 3d colorspace and the pick new colors from the most void areas (on any line)."

It probably won't produce a perfect result (whatever that may be)...but it's a good place to start if you prefer a uniform looking palette.

« Last Edit: July 21, 2011, 06:42:13 pm by DawnBringer »