CHROMiX

Do digicams "see" in sRGB/AdobeRGB/ProPhotoRGB/ or

Do today’s SLR digital cameras (Canon, Nikon, Fuji, etc.) “see” colours that could be characterized as being similar to sRGB or one of the other “editing” colour spaces? Is using a larger space such as AdobeRGB advantageous if the camera doesn’t “see” colours in the far reaches of that space? And if the output destination is an rgb printer such as a lightjet printer, does capturing colours that are outside of the printer’s space serve any purpose, other than to serve up a dose of dissappointment when the print comes back from the lab?

And what is the meaning of life?

Many thanks in advance to all who contribute here!

At 6:22 PM -0800 3/28/05, stuartbish wrote:

Do today’s SLR digital cameras (Canon, Nikon, Fuji, etc.) “see” colours that could be characterized as being similar to sRGB or one of the other “editing” colour spaces?

these are very good questions.

First, a camera doesn’t really have a defined gamut like printers do. A camera will respond to colors in a scene and in most cases it will not limit the gamut of what it can respond to. What I’m talking about here is RAW sensor data such as can be opened in Capture One or the Adobe Camera RAW function of Photoshop.

When a custom profile is created for a camera OR you choose a standard profile (like sRGB, Adobe RGB) in the camera software, then the RAW camera data is ‘interpreted’ and converted into the profile’s space. THEN the camera data is confined to the gamut of the profile.

Is using a larger space such as AdobeRGB advantageous if the camera doesn’t “see” colours in the far reaches of that space?

Tough to say. Because of the way working spaces are defined, you have to ‘pull the corners’ out quite a ways for the overall shape of the gamut to contain many desired colors. So while the colors at the very edges of the gamut may not be desirable, the Adobe RGB gamut size tends to be good for containing most desirable colors… make sense?

And if the output destination is an rgb printer such as a lightjet printer, does capturing colours that are outside of the printer’s space serve any purpose, other than to serve up a dose of dissappointment when the print comes back from the lab?

that is a good question… I have ultimately determined that people (actually, people doing certain functions) roughly fit into 3 categories:

  • input-centric - these are people who want to capture as much detail and fidelity as possible. The rest of the workflow is an evil necessity that will reduce image quality but they want to at least capture the best quality possible in the hopes that things will be better in the future. Large working spaces and 16-bit images are often used here.

  • display-centric - these people just want what’s on the screen to print out. Consumers fall into this group but so do computer artists and 3D people. sRGB is a common working space for this

  • print-centric - these people wonder why we should bother capturing any color we can’t print. They tend to work in smaller RGB spaces (sRGB or ColorMatch) or in device space itself (like SWOP CMYK).

The truth is, all of these views are valid. Some people move from one to another depending on the project at hand. I find that it’s impossible to bend people from one group to another but it helps a lot for people to realize that there are different views AND that they can work together effectively even if they don’t always agree.

Regards,

Steve


o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX


Post generated from email list

I have found that my Nikon D70 has a fairly large gamut. Much larger than sRGB, some what larger than AdobeRGB and almost exactly the same as BetaRGB. For most real world images the camera color space is much larger than the image. But for some images the larger color space is needed to prevent gamut clipping or compression.

For example, I took some photos at an air show last week and one photo was of the 1949 Cleveland Unlimited winner. This FG2U-D1 (one of five built) was painted in a red and white startburst scheme and there was a bright yellow DC-3 in the background. This photo pushed the capabilities of the D70 the limit. When converting it in the raw conversion program from device space (custom profile created with LPROF) to BetaRGB I still had a slight amount of gamut clipping. So sRGB or AdobeRGB would not have even come close to preverving the full gamut of the image.

So the answer is no these devices do not “see” colours that could be characterized as being similar to sRGB or one of the other “editing” colour spaces. They actually see a much larger color space.

As Steve’s explanation goes, digital cameras don’t have their inherent color spaces.
In RAW, colors are interpreted later time, and when shot in JPEG it already
gets confined to sRGB or AdobeRGB, according to user’s setting.
And color spaces that digital cameras can respond are wider than AdobeRGB,
and even wider than sRGB. ProPhoto RGB can contain them all nicely, which is
why it is usually recommended color space when it comes to RAW processing.
It is obvious that the color space is much larger than even high quality inkjet priners,
so it may sound absurd. However the point is that capture is for recording or archiving.
The archived color info may be used for a number of
different purposes. So capture and reproduction are supposed to be one thing
and another. Using AdobeRGB for your digital images can be acceptable but
sRGB means quite a loss.