Adobe PS colour workspace (profiles)

[jase (Jason)]

I'd be interested to know what other astrophotographers are using for their colour workspace settings. Personally, I use a combination of sRGB IEC61966-2.1 and Adobe RGB (1998). Shame, that I can't use just one. sRGB is ideal for displaying your images on the web (assuming you also embed the ICC profile into the jpeg). It would also help if everyone viewing your images has a calibrated monitor. I've calibrated mine as I consider colour accuracy important however I know many others that don't. Just "winging it" sounds too risky for high quality output. The problem with sRGB is the limited gamut range. Thus I also maintain a final image in Adobe RGB (1998) which is better suited to printing (typically CMYK).

What are others doing in this area? How do you manage your colour workflow?

[Dennis]

Okay, I’ll put my hand up and admit that I don’t manage anything at all. Maybe something else I should be exploring?

Cheers

Dennis

[Geoff45 (Geoff)]

I always use Adobe RGB. I calibrate the monitor with Colorvision's Spyder2Pro. When I remember, I save an image in sRGB for web display, but usually I just use a low res Adobe RGB image. I always use the same paper for printing and the manufacturer's inks. I use a custom printer profile ($75 here) and let PS (and not the printer) take care of the colour management.
Geoff

[jase (Jason)]

Thanks for the info Geoff. Yep, I use the same calibration hardware. A query if I may. When you save your images in the sRGB workspace and push them out as jpeg, do you also embed the sRGB ICC profile? Also, when you then load the jpeg into a browser, say Internet Exploder or FireFox do you noticed the colours are not as vibrant? Browsers aren't colourspace aware. I find that I need to subtly boost the colours when pushing the output as jpeg. Do you see this problem?

[[1ponders] (Paul)]

I'm much like Geoff in the I use Adobe RGB (1998) but don't have the funds (read: too stingy to spend on anything else except other equipment ) for a spyder so use the inbuilt Adobe Gamma adjustment. I use the save for web option in photoshop, but I don't know if it converts the 1998 to sRGB or not.

[Geoff45 (Geoff)]

Originally Posted by jase

Thanks for the info Geoff. Yep, I use the same calibration hardware. A query if I may. When you save your images in the sRGB workspace and push them out as jpeg, do you also embed the sRGB ICC profile?

Yes, via the pull down menu Image>Mode>Convert to profile

Originally Posted by jase

Also, when you then load the jpeg into a browser, say Internet Exploder or FireFox do you noticed the colours are not as vibrant? Browsers aren't colourspace aware. I find that I need to subtly boost the colours when pushing the output as jpeg. Do you see this problem?

There are slight differences, but nothing major.
Geoff

[turbo_pascale (Rob)]

Spyder 2 Pro is expensive (About $800 although on sale now for $369), but have a look at the Pantone Huey ($99) or Huey Pro ($189).

Australian Supplier is here: http://www.ausmedia.com.au/pantone-huey_calibration.htm

I have the standard Huey (got it about 1-2 years ago). Have been looking to justify the new one (it has multiple monitor support apparently, which would help as I can't get my LCD and CRT to quite match each other)

I love free stuff as much as the next guy, but $99 isn't too much to ask when you're image editing something you put hours of pain in to capturing it, only to realise that because you haven't calibrated your monitor that you've clipped an image or worse, dragged out too much noise because you didn't notice it.

Turbo

[rally]

Jase,

Here is a Thread that relates to terrestrial photography on a photo forum.
The final explanations in the last few posts cover the issues raised better.

Unfortunately there are many different colour spaces used by devices and systems - all of which have greater or lesser gamut ranges depending on the technology used.
Video is different to a web image on a LCD Monitor is different to a 8+1 ink Epson UltraChrome K3 printer is different Ultrachrome is different to a Euroscale or a Canon 12 ink ImageProGraf printer which is different to offset printing . . . .

Here is an article on sRGB
http://www.w3.org/Graphics/Color/sRGB

Most professional photographers would probably be using aRGB but possibly performing conversions depending on the ultimate use of the image - eg publication on the web (sRGB) or for printing.

The printer (person) then does their own colour space conversion when setting up for a print run based on the process, the inks and the paper being used - sometimes manually or often done automatically by the software.

If you are doing your own "quality" printing this is a function of your printer's own colour profile which is quite dependent on the paper - and so each paper will have its own profile for the most accurate results.
This of course means that the printer's output should get colour calibrated also, although with modern inkjet printers and their inks are becoming so reliable and consistent that this is not as necessary as it once was, but if you cant get a hold of a profile for the paper and printer you are using then you would need to get it calibrated - a service that costs about $50 or is done for free by some suppliers. You print their reference image, they scan it and send you a new printer/paper profile.

The truth is that so long as everyone knows what they are dealing with (ie which colour space the image is and their software has the ability to manage the colour workspace) it shouldn't matter greatly as the same colour information is still retained within the image.
The problems occur when things get mixed up and profiles arent clear, so images with different colour profiles get rendered as if they were the same or by software that doesn't understand or care what to do with the images.
Embedding the colour profile in the image is preferable.

Depending on your OS you may or may not be able to mange your colour space easily - Windows XP has an application direct from Microsoft that allows you to manage your colour profiles - download it - WinColorSetup.exe
Vista is the first Windows OS to allow colour management at the OS level, Mac has had it forever ! Linux uses it with the Gimp natively I think and not much else.

See wikipedia also for further commentary
http://en.wikipedia.org/wiki/Color_management

Its an interesting and not exactly straight forward area that all photographers - astro or otherwise need to standardise their own particular workflow with.

I use aRGB

Cheers Rally

PS calibrating your monitor is essential, although my experience is that many modern quality LCDs are pretty much near correct at factory settings - its usually only the brightness that needs readjusting in the calibration process.

[jase (Jason)]

Thanks for the detailed reply Rally. Much information to go through. I'll commence reading to ensure I'm on the right path. I think if I primarily work in aRGB, then convert to sRGB to upload the images to the web, I should be good. I'll end up with two versions of the same image though - no big deal. Thanks again.

[Garyh]

Interesting and very complex if you want consistency in both display and printing. I just use the Adobe RGB and used Adobe gamma correction for my monitor. With printing I just tweak the paper profile to I am happy with the output.
I usually remove the ICC profile on web posts etc, should I actually leave it in?
cheers

[Geoff45 (Geoff)]

Originally Posted by turbo_pascale

Spyder 2 Pro is expensive (About $800 although on sale now for $369), but have a look at the Pantone Huey ($99) or Huey Pro ($189).


Turbo

Yeah, This is a real ripoff. I got mine last year in the US for $199, so if you happen to go to the US or know someone going there, then this is the best way to buy it. I don´t know how they can justify the Oz prices.
Geoff

[rally]

Jase,

To add further info to this subject
The Jury is not out on aRGB vs sRGB

Here the same question was posted on a photo forum
http://www.fourthirdsphoto.com/vbb/s...ad.php?t=19405

Here's a copy of a link posted in that thread to an article by someone who appears knowledgeable - flies in the face of popular trend.
http://www.kenrockwell.com/tech/adobe-rgb.htm

I think that if you ever have intentions of printing high end images on high end printers or using your images in publications or books then aRGB is recommended.
If not use sRGB.

Being mindful that as each new generation of inks for high end inkjet printers gets released the colour gamut they can print in continues to increase hence making aRGB more advantageous in terms of future proofing your colour space ?


I would say that it would be advantageous never to mix them up if you can help it. So maybe stick with one colour space until such time as you must change.

Being aware that a native aRGB image isn't best for dsiplay on web images - but I cant help but think that the world will get smarter soon and all operating systems and application software will be able to differentiate the images by the exif data contained within each image and render them appropriately. If it doesnt happen it will probably only be because MS doesn't want to support a Mac dominated colour space.

Cheers Rally

[davewaldo]

One thing no-one has mentioned is the colour space in which your digital camera is capturing. If you set you Digital SLR to capture in Adobe RGB then you must convert the raw into Adobe RGB. Even more importantly is if you are shooting JPEG with (Adobe RGB capture) then more often than not the jpeg file does not have the profile embedded and needs to be "Assigned" an adobe RGB colour space (not converted). This will happen automatically if you open a Jpeg into Photoshop (or some other software) if your workspace default is Adobe RGB.

I don't know if you can specify capture colour space on dedicated CCD astro imaging cameras. So I'll let someone else talk about that.

So basically, if you only intend to use sRGB throughout your colour managment, ensure your camera is set to sRGB. Likewise for Adobe RGB.

Just my 2 cents

Dave.

[jase (Jason)]

Whoa, information overload Rally. Thanks mate I've now modified my workflow to commence work in aRGB. Then, I'll save an sRGB copy for uploading to the website. I recently purchased an 21" Eizo ColourEdge LCD monitor. As many in the graphics world will know, these are of very high quality and produce remarkable colour accuracy when calibrated. In my research and discussion with friends I came across a few monitors that displayed the entire Adobe RGB gamut - drool! Talk about wysiwyg! For the humble astro imager I seriously couldn't justify the cost of one, so I settled for the standard sRGB.

Good point Dave. Its important to match the device colour space along the entire workflow. Dedicated CCD astro camera's to output in a specific colour space. Typically in 16-bit FIT's format. You can then convert the images to your preferred format such as 16-bit tiffs and assign the colour space then. Good advice though.

[rally]

Jase,

I found this also
http://www.bythom.com/qadraw.htm

There is some interesting snippets regarding the use of a greatly expanded internal colour space and the final output colour space in processing engines.
under the heading
Raw files do not have a Color Space.

Rally

[jase (Jason)]

Thanks Rally. It reaffirms a few things.

Originally Posted by jase

Dedicated CCD astro camera's to output in a specific colour space. Typically in 16-bit FIT's format.

Just read the above statement, which makes absolutely no sense at all...

What I meant to say is dedicated CCD astro cameras don't output in a specific colour space. The output (typically 16bit fits files) are considered RAW. Only when you covert the images to TIFF files does a colour space become relevant.