PDA

View Full Version : CS3 and colour



hiredgoon
10th March 2008, 10:15 PM
hello hello

i use photoshop and illustrator on both pc and mac. but i am finding that the colour books appear different on the two os. most of the colour is lost in mac version.... looks more greyed down pastel than what it really should look like...

anyone know what the issue is? i did a google and couldnt really find anything...

all colours in other programs appear the same - eg. web sites - red comes out almost exactly the same red on both os...

mab
10th March 2008, 11:04 PM
Windows PCs use 2.2 gamma why Mac's us Mac 1.8 gamma see more here (http://docs.info.apple.com/article.html?artnum=302827)or google for mac pc gamma

hiredgoon
11th March 2008, 08:05 PM
thanks mab. will look in to it and comment later...

Meh 626
11th March 2008, 08:48 PM
I found this gamma situation to be very interesting. I have a few questions.

1. I suppose gamma setting is a personal thing. Am I right?
2. What gamma most represents real life?
3. Why did Mac and PC's go separate ways?

Thanks,

geektechnu
11th March 2008, 09:41 PM
1. Partly. By default PCs do not perform gamma correction at all. 2.0-2.5 is usually the screen's native gamma.

2. In normal light, the PC (because no correction is performed). Macs correct the gamma to 1.8 to reveal more detail in light areas at the expense of tonal range in dark areas.

3. The Mac's roots in print production. A gamma of 1.8 gives great contrast for working in print production, but brightness is skewed towards the white end. For other uses (video, photos, etc.) uncorrected gamma gives a more even tonal range.

sRGB (as endorsed by ICC, W3C, Exif, Pantone, etc) decodes gamma at around 2.2. Ideally 2.2 should be used for videos, photos and the internet - where a full evenly spaced tonal range is preferred.

Also, different gamma values will appear different under different lighting conditions (Aarrgh!)

To further complicate the matter:
- Many LCD screens do not display colour accurately anyway
- If you've calibrated your monitor in the display prefs, it's customised to your specific lighting conditions and display inaccuracies. Only God will know what the true gamma value is now.

Just be glad that we don't have to worry about gamma every time we look at a screen.

bernie234
11th March 2008, 10:16 PM
have both systems been profiled using a spyder......

Meh 626
12th March 2008, 04:35 PM
1. Partly. By default PCs do not perform gamma correction at all. 2.0-2.5 is usually the screen's native gamma.

2. In normal light, the PC (because no correction is performed). Macs correct the gamma to 1.8 to reveal more detail in light areas at the expense of tonal range in dark areas.

3. The Mac's roots in print production. A gamma of 1.8 gives great contrast for working in print production, but brightness is skewed towards the white end. For other uses (video, photos, etc.) uncorrected gamma gives a more even tonal range.

sRGB (as endorsed by ICC, W3C, Exif, Pantone, etc) decodes gamma at around 2.2. Ideally 2.2 should be used for videos, photos and the internet - where a full evenly spaced tonal range is preferred.

Also, different gamma values will appear different under different lighting conditions (Aarrgh!)

To further complicate the matter:
- Many LCD screens do not display colour accurately anyway
- If you've calibrated your monitor in the display prefs, it's customised to your specific lighting conditions and display inaccuracies. Only God will know what the true gamma value is now.

Just be glad that we don't have to worry about gamma every time we look at a screen.

Thanks for your explanation. Really helped.

El Guardo
12th March 2008, 04:43 PM
have both systems been profiled using a spyder......

Sage advice - although if I recall correctly doing so is irrelevant in either XP or Vista after you hibernate or sleep your machine because it drops the profile settings.

hiredgoon
12th March 2008, 04:51 PM
bernie, no spyder calibrations...

What's funny about this is that I shut the computers down after finishing up. Next day I restarted, opened the files, and the colours are now the same! Both displays now show the Pantone colour books in all their vibrant glory.

Now... to confuse me more, I noticed that my "network" display for itsat menus has faded to a dull colour (I have them set to bright red and green)... weird... so... I disconnected my second display AND its the same dull colour on the mbp display?!!

Also; geektechnu, thanks for that explanation, I have been looking around for some other info on the issue!

BLINDER
12th March 2008, 05:33 PM
There's so much confusion surrounding a lot of this.
The ACMP (Aust pro photography assoc. for commercial mag photographers) issued guidelines and this also happens to be a worldwide standard:
Calibrate monitor w/ a hardware device to gamma - 2.2 - whether mac/pc and the D65 standard.
This is THE starting point.
BTW if you're working on photos do it in AdobeRGB(1998) - sRGB is too restrictive.
]But that conversation takes us to a deeper place and can't always be said to be true!