Understanding Rendering Intent for Photographic Inkjet Printing

Test Image: Marshall, Neon BenderTest Image: Marshall, Neon Bender
Test Image: Marshall, Neon Bender

The decision of rendering intent when inkjet printing can be a cryptic problem for most photographers who are printing at home. After all, the very idea of this control is based largely on a crossover from publishing, professional printing and graphic design, and until the digital age, photographers didn’t worry about that kind of stuff (unless they needed a hobby).

I was a graphic design and photo concentration in my undergrad, I’ve been working and teaching in the photography and design fields for nearly 20 years, and I print frequently on the Epson Stylus Pro 3880 and Canon PRO-1. So as someone who has a considerable background this area, in this post I hope to help novices see — and understand — the differences between these confusing settings.  This lesson is also a more in-depth segment of my series on accurate color printing on the Epson Stylus Pro 3880 and SureColor P800; click the links to read my earlier posts on adjusting the feed settings, fixing banding or using ICC profiles.


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Visit Red River PaperBefore I continue with the lesson, I’ll ask for your help up front: When you choose to purchase printing papers such as Hanhemühle, Red River, Epson, Canson or Moab, please do so using the links on this blog. Dick Blick Art Materials provides all the papers listed except for Red River, which provides its paper direct. Whenever you purchase by clicking through from this blog to these sites, it helps pay for all the materials, ink, time and technology I need in order to provide you with these posts. Thanks in advance.

Introduction

The image I show above is our test image for this lesson. If you’ve been following this blog for some time, you’ll know by now I choose images for these posts by how they can help us understand the differences between the workflow or printing settings we’re changing. In the case of this post, I chose “Marshall, Neon Bender” as our subject because of the extreme differences it has between dark and light areas, and because shadow detail is critical to producing a successful final print.

01-Color Management Section
01-Color Management Section

In preparing for the lesson, I used one of my standard proofing papers for lessons, Red River’s Arctic Polar Luster, as it has good color representation and strong details. I then opened “Marshall” in Photoshop and chose File > Print. In the initial dialog that appears, we can see a Rendering Intent section on the right-hand side of the box (See Figure 01). Above it, I selected 16-Bit Printing, and then printed one each of the three Rendering Intent options (Perceptual, Saturation and Relative Colorimetric), and one each with Black Point Compensation selected. I also printed one image using Absolute Colorimetric; this setting does not allow a black point compensation adjustment. This work resulted in seven total prints.

Before I begin, let’s look at the content of this post. First, before I map out the results of my test printing, you should first understand the origins of those cryptic terms used in rendering intent, so I’ll provide some necessary definitions. Second, I’ll provide a table of the four intent terms and their uses. Third, I’ll show you shadow details of the seven sample prints to illustrate the differences in the results of each intent setting, and finally, I’ll wrap up the post with some general comments and suggestions.

Choices, choices: What do those rendering intent terms mean?

Figure 01. ICC Rendering Intent Specification.
Figure 02. ICC Rendering Intent Specification.

I understand how confusing the rendering terms can be, so first I’m going to help explain some of the basics regarding the colors systems in inkjet printing. As you may have read in an earlier post on using color profiles (ICC), we need to tell the printer how to adjust to the type of paper we use, and in the ICC profile is contained a rendering intent specification (see Figure 02) as part of this process.

There are several terms you’ll need to know to make sense of this lesson, and I suggest reading these carefully so they make sense:

Gamut
The total range of colors available to the printer.
Out-of-Gamut
Colors that fall outside the gamut of colors available to a target printer. When colors are “out-of-gamut” the printer must “map” the colors to “in-gamut” colors, and this can result in inaccurate colors in a photograph that “clipped.”
Clipping
A term meaning of out-of-gamut colors that appear solid blocks of a single color.
Black Point Compensation
A Photoshop method of mapping the lowest black point of the source file’s color space so that it generally falls within the gamut of the target printer, resulting in greater detail in dark areas or shadows within the final print. If you are really interested in this, Adobe’s manual on BPC is here (opens in new window).
Perceptual Rendering
A method of rendering intended for photography (and it is sometimes referred to as “Photographic Intent”); the gamut of the file’s color space is completely mapped to the color space of the target device. Colors may be less numerically accurate, but usually more visually faithful to the image as seen by the human eye. Often the specified intent for photo paper providers.
Relative Colorimetric Rendering
A method of mapping the output of the print so that is visually relative to the original file; this way the white point of the file is adjusted to match the white point of the target printer. Other colors are “scaled” according to the mapped white point, and Black Point Compensation should always be used with this rendering setting (if available).
Absolute Colorimetric Rendering
A method of printing intended only for proofing (testing the output of the file before final printing) in the printing industry, where the image is adjusted to simulate the paper and gamut of the target printing press. Not recommended for photographic printing.
Saturation Rendering
A method of “pulling” the most saturated colors to the gamut edge, increasing the visual “pop” of the colors. Not recommended for photographic printing.

 With these terms in mind, let’s move on to how these intents compare, and how paper companies use them.

Paper manufacturers have rendering preferences. You should, too.

As the section headline suggests, and Figure 01 shows, yes, paper manufacturers specify an ideal rendering intent for each of their papers in the respective ICC profile. Each rendering intent has a specific use, and while I know you would love to make your own table comparing each, I’ve taken the time to do it for you (I can hear my former assistant chiding, “Don’t get cheeky, Brett.”).

 

Table 01. Rendering Intent Comparison
Intent Name Purpose BPC? Recommendation
Perceptual Photography Yes Good
Relative Colorimetric Photography and Image Printing Yes Good
Absolute Colorimetric Printing Proofing No Poor
Saturation Logos, Graphics Yes Poor

* Black Point Compensation Available

 

If you spend some moments looking through the table, you’ll notice I give my strongest preference to Perceptual Rendering with Black Point Compensation and Relative Colorimetric with Black Point Compensation. This results from most photo printing paper manufacturers prioritizing this method, and when the paper is made with an intent in mind, that’s usually the best intent to use. Moreover, as you will see in the next section, these show the best results.

Test Results

I’m including the test result images here. Each was shot with a Sony A7R on Raw with a 100mm macro lens under a single copy stand bulb, then imported to Lightroom and brightened by +1.00 exposure to reveal any shadow clipping. I apologize for some of the dust and scratches; I initially tried scanning the images at 600 dpi into PDF format, but this proved too lossy for this test; since detail in the shadows is our focus, the surface artifacts don’t play a role in our decision making. I’ve placed the images in a click-through gallery at full size to help illustrate the differences in shadow detail, so click the top-left image to begin.

 

 

 

At first glance, the results may seem similar. However, if you take time to examine the shadows on the side of Marshall’s face, it becomes clear that the Saturation and Absolute Colorimetric intents seem “posterized” (flat shadows, little detail, abrupt transitions between shadow and lighter areas), and the Relative Colorimetric and Perceptual intents without BPC also lose significant detail in the facial shadows. Perceptual + Black Point Compensation shows some minor improvements, but in the case of this image, clearly the Relative Colorimetric with Black Point Compensation shows the most pronounced detail in the shadows. While the detail is exaggerated due to my adding the +1.00 exposure value in Lightroom, the simple fact remains that we now know the most appropriate rendering intent setting for this image.

Conclusion

In the end, our test results revealing Relative Colorimetric with Black Point Compensation as the best Rendering Intent setting choice for “Marshall, Neon Bender” is as unique as any image itself. I often use Perceptual with Black Point Compensation, but this test shows that’s obviously not always the best setting. Surprised? I was, too; I expected Perceptual to be the winner, and I was dead wrong.

Our lesson here is a common one on this blog. As you may be getting used to by now if you’re a regular reader, your smartest bet when printing your important images is to run this same test on your own studio system and use a 5x or 15x loupe to check the results. In that way, you’ll know exactly the right intent settings for your masterpiece. For the “Marshall” image, which needs strong detail in the shadows, Relative Colorimetric with BPC is my choice. If deep, rich blacks that create powerful drama were the most important part of the image, I’d choose Perceptual with BPC. As you can see, the testing process and a strong knowledge of the visual purpose of the image help determine the ideal settings for getting the most out of our print.

And as always, I hope your best print…is the next one.

Questions or comments? Please be respectful, and leave them below so that the conversation can benefit others who are interested in this topic.

4 thoughts

  1. Wow…An amazing Article, Very well presented, and really wish to thank you for taking the time and showing us such fine examples!!! Big Props to ya!!++++++++

    1. Don,

      You’re very kind. I’m even more glad it helped! Rendering and color work is a bit like learning a new language–or hieroglyphics–for many folks, and it is very satisfying to know the article helped.

      Brett

  2. Hi Brett
    late to the show, but neverless, this article is VERY helpful! I’m just “learning” how to print photos (on a a good printer), fell on my nose, Now I understand the effect of BPC, will have to try and see.
    Thanks a lot
    George

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