Sijun Forums :: View topic - Mac and PC Gamma issues, Please read this,

TylerHunter · Posted: Fri Nov 09, 2001 1:47 pm

I came to notice people complaining about a painting by Craig Mullins being too dark. Knowing that Mullins uses a mac. I loaded it in PS and adjusted the preview gamma to Mac. WOW, the difference was phenominal. So I must stress the issue that when viewing his work or any work produced on the mac, please take the time to preview them in the right gamma format. PC art will look very light on mac systems and mac art will look dark on PC systems. I suggest that people post which type of platform the art was produced on. Any comments on this issue would be nice. This may be a well known issue but I've seen numerous complaints about art due to such an issue.

Thanks
Tyler

Pat · Posted: Fri Nov 09, 2001 3:33 pm

A lot of Mac guys do work professionally, either in print, video, etc, so their gamma is mandated by the media. Out of the box PC gamma, IMO, is way off. My PC friends who do print work all have their systems callibated properly so artwork looks the same cross-platform.

-Pat

TylerHunter · Posted: Fri Nov 09, 2001 11:31 pm

Boy do I feel dumb, woops forgot about calibrating my video card.. hahahahaha!!!

oh well we all have brain farts.

worthless_meat_sack · member Member # Joined: 29 May 2000 Posts: 141

Pat,

How would this be done? I have no idea. I guess I could crank down my monitor to what a PC is?

I wish Danny G were here...

jeffery · Posted: Sat Nov 10, 2001 12:31 am

yeah i'd love to get a step-by-step guide for monitor calibration. i've tried doing it thru photoshop, but i find the process kind of confusing, as there seems to be no "right" answer..

Pat · Posted: Sat Nov 10, 2001 12:58 am

worthless_meat_sack,

It's kind of a moot point. I'd keep your monitor callibated for what it's primary use is and not worry about how people are seeing your work. For one, the gamma issue is usually overstated. We're talking, on average, a +15 on the old Photoshop brightness/contrast scale. Images with proper amounts of contrast don't suffer much to begin with.

Anyway, the accepted method of accurately converting a Mac image to standard PC gamma is as follows:

1) Make sure you're on the Photoshop default gamma of 1.8. File>Color Settings>RGB Setup

2) Convert your image from RGB to LAB color.

3) Change the RGB setup from 1.8 to 2.5 gamma. Image will look washed out. That's ok though, that's what PC users need to have to see the image as you created it.

4) Convert the image back to RGB and save. It should retain it's washed out features.

5) Reset your Photoshop gamma back to 1.8

You can bypass all this nonsense by saving your images as .png files, since that format contains embedded gamma encoding. There's a bug in Netscape though, which prevents the encoded gamma from displaying properly, but it works fine in Explorer.

Hope this helps.

-Pat

worthless_meat_sack · member Member # Joined: 29 May 2000 Posts: 141

Tanx, Pat. I agree.

I my particular case, I like a darker key to start with. If this was created on a mac, the darker gamma of a PC is going to make it fall of the deep end.

Most of the images of my site were done before i was aware of this problem. To fix it, I would have to go back to the source files and redo the whole thing. Yack. Not going to happen.

I will adjust my mac screen to match my pc screen. Same file, same data, play with screen controls till it matches.

Pat · Posted: Sat Nov 10, 2001 3:50 pm

worthless_meat_sack,

I should have suggested you use the Adobe Gamma Control panel to calibrate your gamma. It's kind of the software version of the brightness/contrast/color controls on your monitor. It's cool because you can save different gamma settings for different occasions ie: one for games, one for Photoshop, one for video work and one for the web. I just stick an alias for the Gamma control panel in my "Startup Items" folder on the Mac and it boots automatically after the system.

-Pat

Mr Sootie · Posted: Sat Nov 10, 2001 5:29 pm

A good site to check out is the Acurate Image Manipulation site at http://aim-dtp.net/ . In particular the page on system calibration: http://aim-dtp.net/aim/calibration/index.htm . Theres also good section on how to calibrate your monitor properly at: http://aim-dtp.net/aim/calibration/blackpoint/crt_brightness_and_contrast.htm Its a very handy site and has information on both pc and mac.

[ November 10, 2001: Message edited by: Mr Sootie ]

Dr.Squirley · Posted: Sat Nov 10, 2001 7:18 pm

if find is not always that pcs are darker and macs lighter. it varies monitor to monitor and less os to os. i simply have my pc monitors adjusted up and my mac down. and its not that dificult, most can access the gamma correction in their video cards properties.

[ November 10, 2001: Message edited by: Dr.Squirley ]