Understanding the difference between assigning and converting to a profile is one of the most conceptually challenging things about color management in digital imaging. It’s counterintuitive to think that by changing numbers the appearance of colors will stay the same or that if you don’t they won’t. But, once you understand why this is happening, how to set up your color management environment and what to do when you encounter color management dialog boxes will become much clearer.

In color management you “change to stay the same”. Why? Take the values for the most saturated red in any RGB color space – 255/0/0. If you graph this in sRGB (a small color space) and ProPhoto RGB (a large color space), you can quickly see that one will produce a much less saturated red than the other. Similarly, all the other numerical combinations produce different appearances in different color spaces too, with the exception of absolutely neutral colors whose values are equal – i.e. 128/128/128. To maintain the appearance of colors when you move them from one color space to another (for instance from a monitor to a printer), you have to change the numbers very precisely, using ICC profiles or maps for each color space and recipes for mixing colors in them.

The parenthetical remarks in Photoshop’s Paste Profile Mismatch dialog box say it clearly.

If you Don’t Convert but “preserve color numbers”, the appearance of a file will change, sometimes dramatically, because the numbers in the file have not been converted but a new color profile has been assigned, changing the meaning of the numbers.

If you Convert you “preserve color appearance”; Photoshop does this by referencing the ICC profiles of the source and destination color spaces and precisely changing the numbers in the file so that they produce the closest possible match to the original appearance; only the appearance of very saturated colors will change if you convert a file to a smaller gamut color space.

Note that information converted from sRGB into ProPhoto RGB does not get more saturated. The editing space becomes wider gamut, but the potential for increased saturation can’t be accessed unless values in the file are further enhanced with software. The best way to get the most saturated color possible is to convert the source file (Raw) into ProPhoto RGB.

If you adopt a consistent workflow and always convert into and create new files in the same color space, you’ll encounter these dialog boxes infrequently. You’ll quickly find you won’t have to think about it any more. And when you do, you’ll simply take appropriate action with confidence when you need to, confident that the images you’re creating are the very best that can be created.

Remember, color management isn’t about ensuring that color doesn’t change, it’s about ensuring it changes as little as possible and is changed as precisely as possible.

Read more in my color management ebooks.

View more in my color management DVD.

Learn more in my digital photography and digital printing workshops.

If you want to display your images accurately, and make sophisticated decisions about how they will or could look, calibrate your monitor with hardware. Monitor calibration is a must. It’s not optional. It is easy. You need a device to do it well.

The visual comparator method (using your eyes to approximate an appearance on screen) is too fraught with inaccuracies and inconsistencies to be relied on. Instead, use consistent, accurate, objective hardware and software. Colorimeters don’t have favorite and least favorite colors, don’t have color deficiencies, don’t get fatigued, don’t drink caffeine or eat sugar, don’t change over time or adapt to their environments, and don’t have emotions. You do. All of these can affect your perception of color at one time or another. Colorimeters are in a stable state. You’re not. So when it comes to making sure that your monitor displays color as accurately as possible, use a colorimeter.

While some colorimeters, and the software packages that ship with them, are better than others, most colorimeters are good. Unless it’s defective, any colorimeter is better than none.

Spectrophotometers can also be use to calibrate monitors. What’s the difference between the two? Unlike a colorimeter, a spectrophotometer has it’s own light source that can be used to make printer profiles. Spectrophotometers can do more. They also cost more.

There is a difference between calibrating and characterizing devices. Calibrating a device is changing its state, like setting the brightness of a monitor. Characterizing a device is measuring and mapping the color capacity of a device or building an ICC profile to describe it. Most of the process of monitor ‘calibration’ is actually ‘characterization’.

Calibrating and characterizing your monitor is a simple process. Use the profiling device and software of your choice. (I personally use X-Rite products.)

Take these steps. Read more

gamut clipping

gamut compression

Your choice of a rendering intent tells a color management system how to handle color conversions between different color spaces. This is particularly important when converting colors from a wider-gamut color space (such as an editing space like ProPhoto) to a smaller-gamut color space (like a printer color space). You’ll get different results, even when using the same ICC profile, depending on the rendering intent you choose for a color conversion. You have four choices; perceptual, relative colorimetric, absolute colorimetric, and saturation.

What’s the difference between these four rendering intents?

Here’s the get it done explanation.

Perceptual
Use a perceptual rendering intent for printing images with highly saturated colors. Watch it carefully. To deliver very saturated colors, it may lighten an image or shift the hue of specific colors. Both side-effects can be compensated for with output specific adjustments.

Relative Colorimetric
Use a relative colorimetric rendering intent for printing images where the luminosity structure is most important. You may get slightly less saturated colors but brightness values will be most stable with this rendering intent. This makes it the ideal choice for near neutral and black and white images.

Absolute Colorimetric
Use an absolute colorimetric rendering intent for making a proof of one device on another, like making a proof of an offset press on an inkjet printer. It’s not useful for making the best inkjet print; it will limit the results the printer delivers. Note, you can’t simulate a printer with a greater gamut than the device you’re printing on, only one with a smaller gamut.

Saturation
Use a saturation rendering intent for eye-catching graphics where color impact is more important than color accuracy , like pie charts. It will so much saturation it will distort continuous tone images in an adverse way.

Here’s the color geek explanation. Read more

Today’s inksets can exceed the gamut of even the best monitors in yellows, oranges, and blues. Epson UltraChrome HDR ink on Epson Exhibition Fiber is plotted against sRGB, Adobe RGB (1998) and ProPhoto.

The gamut of this image and the print made from it exceeds the gamut of Adobe RGB (1998) and the monitor. You have to make a print to see the most saturated color possible.

Choose a wide gamut editing space to make the best prints possible. If a file’s color space is smaller than the printer’s color space, you won’t be able to realize the full saturation your printer is capable of.

Today’s inksets exceed the gamut of all but one of the standard editing spaces (sRGB, Colormatch, and Adobe RGB (1998)), making ProPhoto the best choice for creating files in. Since ProPhoto exceeds the gamut of human vision, it’s unlikely that you’ll ever need a wider gamut editing space than ProPhoto. If you create your files in ProPhoto you’ll be well positioned to take advantage of future advances in printer and media technology. So, choose ProPhoto.

How do you do this?

1         If you’re converting a Raw file, choose ProPhoto in the Raw converter’s interface.

2         If you’re exporting a file from Lightroom, choose ProPhoto.

3         If you’re creating a new file in Photoshop, set ProPhoto as your default color space.

4         If you’re scanning an image, choose ProPhoto in the scanner’s interface.

Read more

ICC profiles define a meaning for the numbers used to represent colors in digital images. Without an ICC profile digital files will produce unpredictable and inconsistent results.

As a rule, always use ICC profiles. There are a few rules for using ICC profiles. Always assign ICC profiles (the correct ICC profile) when you create a digital file. Always use ICC profiles when converting digital files from one color space to another. Never remove an ICC profile from a digital file without replacing it. Use accurate high quality ICC profiles. While there are exceptions to these rules, they’re rarely encountered.

Here’s one of the single most confusing things about color management. The same numbers in different color spaces produce different colors. Why? Because while RGB color spaces (including the standard device neutral editing spaces sRGB, Colormatch, Adobe 1998, ProPhoto) all use the same numbers from 0–255 to describe color, each color space is capable of different things. For instance, wider gamut color spaces are able to represent more saturated colors. The numbers used to produce the most saturated red (255/0/0) will produce a more saturated red in a wider gamut color space than they will in a smaller gamut color space. So the same numbers in different color spaces produce different results.

Here’s another way of saying the same thing: Change to stay the same. Use ICC profiles to define a source and destination so you can change numbers precisely to make sure colors stay the same. Once you know what numbers you need to produce the same color in two different color spaces (like a monitor and a printer), you can precisely change the numbers to produce the same color appearance as you move a digital image from one color space to another. If you don’t change the numbers, the appearance of the colors will change when you move a digital image from one device/color space to another.

Some change is inevitable when moving from a larger color space to a smaller gamut color space and ICC profiles can be used to predict how color will change. They can be used to show you what must change and can’t be restored (out of gamut colors) and what will change and can be restored (in gamut colors). While you won’t gain color quality when converting from smaller gamut spaces to larger gamut color spaces, you’ll lose a tiny bit of data, which if done a number of times can degrade an image. So, keep color conversions to a minimum. (Optimally, convert once when you acquire an image; a second temporary conversion will be made while you print an image).

Use ICC profiles. ICC profiles are recipes for color that clearly define numbers making color consistent and predictable. They’re the foundation for working with color in digital imaging.

How important is this?

See what can happen below if you don’t use ICC profiles correctly.

Read more

X-Rite i1Photo Pro

April 8, 2011 | 2 Comments |

“The long awaited day is here!  X-Rite i1 Professional solutions, which includes the new i1Photo Pro, are now available. Each solution features the all-new i1Profiler software application designed to delivers superior color results!  i1Profiler is driven by a new color engine, sports a dual mode interface (basic and advanced) and new quality assurance features, plus so much more. The new i1Photo Pro was designed specifically for discerning photographers to attain the highest quality color results and color control throughout your complex digital photo workflow, at a very attractive price.

The new portfolio is comprised of three software/hardware/target bundles ­– i1Basic Pro, i1Photo Pro, i1Publish Pro – and i1Publish, a software/target solution. All four feature groundbreaking new i1Profiler software technology designed to accommodate all levels of proficiency and expertise, and provide the power and control needed to create the highest quality color profiles. The new PANTONE Color Manager color swatch bridging software,  ColorChecker Proof, a new ColorChecker target for direct viewing analysis against a printed target and ColorChecker camera calibration system are also featured.

Upgrade packages are available for those who have i1Pro devices as well as MonacoPROFILER 4 and ProfileMaker 5 users. Read more about the upgrade opportunities and review the features of i1Profiler software at www.xritephoto.com.”

The advances in software make every function more precise.
Printer profiling takes a major leap forward with easy to make light temperature and image specific profiles.

If you haven’t invested in X-Rite technology do it now.
If you have, upgrade now.
This is a major upgrade that all users should seriously consider.

Find out more about i1Photo Pro here.

View more in my DVD 6 Simple Steps to Good Color Management.

Learn more in my digital printing and digital photography workshops here.


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