Why use a color managed workflow?

[NikonErik]

(I'm not sure if this is the right place for this, please relocate if necessary.)

The other day someone asked me about color management, monitor calibration and the use of profiles. Geeze, this guy knew how to get me going!

On another message board Member "DrGsin" asked me:

Quite a while back, E recommended I use Costco to process my photos. I performed a little test between them and another printer-whom I thought would be superior and sure enough, E was right. So Ive been using them ever since and getting some great results. Recently I purchased a high end LCD (NEC 2490) for the specific purpose of using it for photography. Ive color calibrated it and my Lacie CRT and other than the lcd being slightly brighter, the colors seem to match each other well. CRT is @max brightness and lcd is @ min brightness by the way. The calibrating software(ione) installs the profiles for each screen into the control settings of my computer. Anyways, to make a long story even longer, up until I calibrated everything, I used the auto correct feature that Costco provides. On the whole I think it did really well, but I like my colors a bit punchier, so I downloaded the color profiles that Costco uses for their type of machine and the types of finishes-glossy and lustre, or matte as Ive known it. My question, finally, is: where do these new profiles go and how/when do I use them? Do I convert to this profile when I open up the pic in PSNX? If I understand this correctly, Id be replacing the calibrated profiles for the costco profiles, no? If thats the case why would I even calibrate my monitors? Or...do my calibrated profiles allow me to view the costco profiles as theyre meant to be seen? Im using sRGB from in camera thru NX thru PS thru Costco-since Costco doesnt print in aRGB.

Thanks!

Read on for my reply which has some unique information for the Biorust community:

[NikonErik]

Each method for reproduing colors does it in a different way, right?

(All of The following may not apply to Raw capture)

From the beginning . . .

Every imaging device has a signature look we call a profile. When you capture an image and write a jpeg, your camera has it's profile. That is to say that it re-produces the colors it captured in it's own way. Miuch like a Fujifilm vs. Kodak film comparison, Nikon and Canon each have their looks to them. Some of you (not me) could probably guess the brand of the camera just by looking at the image.

To make things more complicated, some cameras have more than one "box of crayons" or gamut with which to interpret the sensor data when creating the file. Regardless of which gamut you use, someone looking to work as smartly as possible will consider where the the file goes next.

You may have noticed that ACR, and LR have camera calibration control panels. This is how photographers and studios dealing with multiple cameras and camera systems can get similar color reproduction when importing the catalogs.

The colorimeter you used to calibrate the monitor sent standard RGB recipes (standard colors) to the monitor. The optical colorimeter looked at your monitor during this process and decided in a precise manner how "off" your monitor was when displaying these colors. The software then creates a conversion index profile for that monitor. This way RGB recipe 46, 185, 108 looks like THAT COLOR when displayed on your screen. Without calibration 46, 185, 108 could look like 46, 185, 164 - which is blue shifted, but only subtly so. If your monitor is more blue shifted, or cooler than than your commercial clients monitor, then this could easily be a reason they are getting on your back because their products are the wrong color in your proofs. It could be why Bridezilla is calling you because her $10,000 Ivory dress looks Virgin White in her proof set. (true stories - I calibrated their monitors for them and voila!)

Okay, now you have a profile that looks at your specific monitors to ensure that the colors optically look the way they are supposed to. Next you get to have all of the fun with your software and make things look fine and dandy!

Folks with multiple monitors my want to use a system that is specifically designed to ensure that both monitors make the colors look the same across both of them.

The next problem you face is when you consider that the printer you use will also use its own unique recipe to reproduce the colors. We can only hope that they profile their machines to ensure that 46, 185, 108 looks correct on their paper when the images are printed.

Here's the kicker: Our monitors produce A LOT more colors, particularly more saturated colors that most printers can!

Have a look at this:

The term "Gamut" refers to what I like to describe as the "box of crayons" that's available to your image reproduction device. No two devices have the same "box." Crayola's "blue" crayon is different, I am sure, than Rose Art's "blue". The range of colors a reproduction system can create is mapped on a 3-D grid, or 3-D space.

Below you see two 3-D Gamut maps centered on each other on a 3-axis space based on Lab color (as opposed to RGB). Lab color space was designed to represent colors that is more like the way we see. In Lab space, the vertical axis represents Luminosity (white to black). Another axis represents the "a" axis which is the range of colors between green and red. Finally the 'b" axis which is the range between yellow and blue. See this HP ColorSpan page for a cool graphic and simple explanation.

I rotated the graph to show top and sides . . .


In the above screen captures I am comparing my calibrated monitors profile with the smaller one that Costco can reproduce. The gray represents my (pretty good) monitors capabilities. Notice the Costco gamut resides almost entirely inside of the monitors gamut-space.

By the way, the best machine at White House Custom Color, one of America's most advertised "high end" service bureaus (I love to use these guys) has a gamut only a wee-bit broader in the reds than Costco. I have a macro image of a rose that is out of Gamut for most labs that I'd like to use to print the image. Oh well, I'll enjoy it on the screen!

If it just occurred to you that your images color range may not be getting printed, then you are catching on!

What do you do??

Read on . . .

[NikonErik]

The art and science to all of this happens when you "soft proof" in Photoshop, Nikon NX, Lightroom or any other app that can do it.

Soft Proofing allows you to use the labs profile to simulate on your monitor how it will look on their paper before it is printed-out of their (properly calibrated, maintained and operated) machine.

You see, Costco and other decent labs use services like Dry Creek Photo regularly. They send them a print of an industry standard image every so often. DCP will then opticaly examine the print and generate a profile for that machine. Now we know in a labratory setting what 46, 185, 108 looks like when printed by that machine. We also know what corrections that machine needs to make in order for 46, 185, 108 to look like it is supposed to.

**More importantly, we also know IF 46, 185, 108 can be printed at all!

If it can't, and you have a lot of this shade of green in your image you are going to notice a big difference when you get the image back from this lab.

Okay, now we know what can happen, how do we deal with it? By Soft Proofing, you can simulate how the image will look when printed by the machine you intend to use. You can now safely color correct, set your black and white points, and establish the tonal range WITHIN THE GAMUT OF THE PRINTER. Before, you were doing it in the gamut of your monitor!

What happens to the colors that the printer can't reproduce?

Good question! . . . read on . . .

[NikonErik]

Now we get into the tricky part of color management. If you have an image that looks great and colorful on your screen you should have a look at how it'll look when you print it . . . using a printer profile give you the ability to get a very good idea of what the image is going to look like when it's printed.

All of our cameras WILL capture more than your screen can reproduce. The screen WILL reporduce more colors than what virtually all of the printers (that we can afford to use!) can produce.

When you soft proof, you'll see where the colors drop off and what'll happen to your contrast etc.

I wrote about this in great detail a while back.

Please read:

On Color Management and Workflow

Microsoft Color Control Applet (Windows) Great for installing and managing profiles.

[NikonErik]

(Finally I wrote)

There's more I wanted to share about this. I wrote up another full panel than accidentally closed the window of my browser! Then it was just late. All I could muster was my last post up there. Sorry it was so abrupt. I'll get back to this thread soon and tell you about colormetric conversions . . .

[Flipper]

Very interesting Erik. Your detailed explanation is brilliant

I have recently purchased a Nikon D80 & 80-200mmVR lens. Still getting used to the camera's manual settings but this thread has given me a far greater understanding for the importance of monitor / printer calibration. THANKS.

Cheers.

[NikonErik]

I am so glad that this write-up has been appreciated as much as it has. I plan on writing about Colormetric Conversions in a new post soon.

[unleash]

Woot,
Im not much of a photographer myself( my dad is) but this thread is really handy...
photographs are not the only things that can be printed!!

Just an idea, but wouldn't this thread fit into the wiki perfectly??

anyway, +rep frome me

[Man1c M0g]

Originally Posted by unleash

Woot,
Im not much of a photographer myself( my dad is) but this thread is really handy...
photographs are not the only things that can be printed!!

Just an idea, but wouldn't this thread fit into the wiki perfectly??

anyway, +rep frome me

Actually, I'm thinking of making a 'photography techique' section for tutorials, and this would fit the bill nicely! I'll get around to converting it after I upload NikonErik's other tutorial (no, I haven't forgotten! ).

[NikonErik]

Understanding the basic principles of color management empowers the user to consider the reproduction device that will ultimately reproduce the image. As I said above, many image editors today will now provide a means to simulate the the way an image file will look when reproduced with another device. The use of these tools is called "soft proofing."

I "soft proof" in Photoshop whenever I am looking to print something where my colors are critical to the success of the image.

In Photoshop on a PC: View>Proof Setup>Custom

Many of the image editors with color management options will also allow you to make a decision about what you want to do with the colors that are outside of the gamut of your chosen output device. In other words, if the printer you are using can't reproduce all of those colors, to that level of saturation, what do you want to do with the file? That is to say, your color management system is asking you, "what is your rendering intent?"

There are four basic rendering intents to choose from in Photoshop. (I'll explain a little about each in a moment)

• Perceptual - Best for photography, not for accurate color reproduction.
• Relative - Good for photography, good when color accuracy is important.*
• Saturation - Good for business graphics, and logos where "color pop" is most important. Very bad for reliable color reproduction.
• Absolute - Best used for soft proofing only. May use the white of the paper stock as the white point of the gamut, thus shifting everything accordingly. Good to use when printing on paper that is not bright white, or non-white.

Sounds like a lot? It's not too bad, really . . . read on!

[NikonErik]

Hopefully, many of our images are not too "out of gamut" for most of the printers we use. Usually, wider gamuts mean more saturated, vibrant colors than the narrower ones. When we soft proof and view an image in a narrower gamut, we are usually seeing how the image will look with less saturated colors. The rendering intent you choose may also effect the in-gamut colors too! -This may be a good thing, or not. It depends on the image, and the viewers taste.

On the one hand, it's perfectly okay to try each of the rendering intents to see which one gives you the most pleasing version of your image.

On the other, I like to know a little bit about what is going on, because I know that the range of colors of my image can and will be shifted around depending on which rendering intent I choose.

From here on, it is given that there are some colors in our image are within the gamut of the chosen printer, and some colors are out of gamut, and cannot be reproduced without colorimetric rendering . . . Photoshop gives a few choices

Perceptual Intent: This rendering intent is best suited for photography. This is because it will maintain the relationship between the colors in the image so it (hopefully) continues to make sense visually. This is achieved by compressing the entire range of colors in the image to entirely fit within the printers gamut. This means the original colors that were reproducible get shifted too. Out of gamut colors will get compressed to gamut, sometimes will within gamut. As per Photoshop Help, "This is the standard rendering intent in Japan."

Saturation Intent: Similar to Perceptual Intent in that the in-gamut colors will get compressed. The difference here is that the intention is to maintain a saturated look. This is achieved by compressing the out of gamut colors to their nearest in-gamut neighbors that live on the outer edges of the in-gamut map. The colors that were already in-gamut had to be compressed in order to maintain their distance from the out of gamut ones in order to maintain the saturated look.

The next two rendering intents are interesting because they deal significantly with the fact that different gamuts, or color spaces have white points in slightly different locations relative to the entire "reference space" that we use to represent all viewable colors. (Please play with your cameras White Balance to experience the significance of where the White Point lives.)

Relative Intent: This one gets its name because it shifts the white point of the starting color space to the white point of the destination color space, shifting all colors with it. Furthermore, it will clip the out of gamut colors and only maintain the in-gamut ones. This is okay for photography, particularly when there are few saturated, out of gamut colors. From Photoshop Help, "Relative Colorimetric preserves more of the original colors in an image than Perceptual. This is the standard rendering intent for printing in North America and Europe."

Absolute Intent: This one is the most exotic, in my opinion, and the most useless to photographers. It may be the MOST USEFUL for graphic artists, and printers. This Rendering intent behaves a lot like Relative Intent but does not adapt the white point to the new color space. This Rendering Intent is used to simulate how the color of the paper-media effects the white balance of the destination gamut. If the color profile being used was made by metering colors off of newsprint or ivory card stock, then soft proofing with this rendering intent will produce the proper color caste of the source paper. In other words, if the white point was defined as the white of clean newsprint, or as the ivory of the greeting card stock, then soft proofing with this intent will shift the white point as you see it on your monitor to simulate the look of these papers.

[NikonErik]

Here are some examples of what the rendering intents will do to an image that is greatly out of gamut for a given printer. In this case I used a profile for the glossy paper from a Noritsu system at my local Costco.

Please comments and observations below: