This document provides basic instructions for people who:
- work with RGB images, whether created in Photoshop or captured with a digital camera or scanner,
- wish to print their images on an inkjet printer.
This document does not address the needs of people who:
- need measurable color accuracy,
- only wish to post their images to the web,
- print their images by sending them to an online service,
- are preparing images for a printing press,
- work with images in the CMYK color mode.
Color Management refers to the technology and processes used to insure that colors are presented as closely as possible to the way they're intended on multiple devices. No display device or printer can show the range of brightness and color that the human eye can see, and no two devices (including different kinds of printing paper) display exactly the same range of brightness and color.
Further, different devices of the same kind respond differently: if you unplug one model of monitor and plug in another without changing any software settings, images will look different on the new monitor. If you change paper in your printer without changing any software settings, images will look different on the new paper.
Color management addresses these issues. You can get quite good results with minimal equipment and a small investment of time in some simple procedures. If you require results with extreme and measurable accuracy, more complex procedures and equipment are required. This document is biased strongly toward the simple end of that scale. Color management can get you as close as physics allows, but there will always be a difference between monitor and print (see below). Most importantly, color management makes that difference consistent and predictable. Your prints won’t be green sometimes and pink other times, or unpredictably dark or light.
Color management is based on the use of color profiles. For our purposes, there are two kinds of color profiles:
- Working profiles are associated with a document in Photoshop, such as an image captured by a digital camera. They describe how the RGB values in the document correspond to the actual colors that we see, and determines which colors can be represented in the document. The working profile of a document is set when that document is created, whether it’s a JPEG file from a digital camera or scanner, a new document created in Photoshop, or a document created by opening a digital camera RAW image in Adobe Camera Raw. The two most common working profiles are sRGB and AdobeRGB.
1. The ProPhotoRGB. This color space is used by people who want to make sure they are retaining all the color information possible from their image captures. It’s one of those “you probably only want to use it if you already know why you want to use it” features, and is more appropriate for highest-end printers. The most important thing to know about using ProPhotoRGB as a working space is that to avoid paying for those extra colors with a greater risk of banding (visible steps between colors) in your images, you should work in 16 bit mode. ProPhotoRGB can represent many more colors than even AdobeRGB, including a relatively small slice of colors that high end inkjet printers can print that cannot be represented in AdobeRGB. It also includes a huge number of colors that digital cameras can capture but that can’t be displayed on any output device or printer, and even more colors that humans can see but that can’t be captured with any input device or displayed by any output device. What’s the use of all these colors if you can’t display or print them? First, you can be sure you haven’t thrown away any information that your camera captured until you absolutely must (when you output the file). For example, you could make a big hue / saturation change that moves previously unviewable and unprintable range of purplish reds into a range of deep blues that can be displayed. Or you might perform a sequence of editing steps that temporarily create extreme, unprintable colors and then later restore them to a printable range (say, by boosting overall color saturation and then cutting it back in specific areas). Having all those extra colors lets you do this without destroying color differences in the image. But ProPhotoRGB comes with a cost: To avoid banding you should work in 16 bit mode, which doubles file sizes, memory requirements, and operation times. Most Photoshop operations are available in 16 bit mode, but many of the creative filter operations are not.
AdobeRGB can represent more colors than sRGB — specifically including more saturated colors that inkjet printers can print. This profile is most appropriate for mid-range printers. So if you plan to print your images on an inkjet printer, you may wish to use AdobeRGB as your working space. You do this by setting your digital camera or scanner software to output AdobeRGB files, setting the output settings within Adobe Camera Raw to output AdobeRGB files, or, if creating documents from scratch in Photoshop, selecting Adobe RGB from the Color Profile pop-up in the advanced section of the New Document dialog.
sRGB can represent fewer colors than AdobeRGB, and inkjet printers can print many of those colors. This profile is best for all-in-one printers (that include a scanner and/or fax). So if you use sRGB, you will never see some of the more saturated colors that your digital camera or scanner can capture and your printer could print. But sRGB does include the vast majority of colors in the vast majority of images. Most monitors connected to the Internet are not color managed in any way, but they have device profiles that are close to sRGB, and many online print services require files that they print to have a working profile of sRGB. That means that for files to be posted on the internet or sent to such an online service, you should either use a working space of sRGB, or convert the file to sRGB before posting or sending it. You can convert a document to sRGB either by choosing Edit >Convert to Profile, and choosing sRGB as the Destination Space (leave other settings as they are), or by selecting the Convert To sRGB checkbox in the Save For Web And Devices dialog when saving a JPEG for the web.
Set up a reasonable and consistent lighting environment for the monitor you use for editing.
- Low lighting that doesn’t vary much by time of day and has no light sources falling directly on the screen is ideal (you don’t want to see reflections of lights or bright objects in the screen when it’s off). Conversely, the worst possible setup would be one in which the sun shines on your monitor in the morning and in your face in the afternoon.
Profile and calibrate the monitor every 6 months or so.
- Even the least expensive modern monitor calibrators (under $150) will produce more accurate and consistent results than the software calibration functions built into the Mac and Windows operating systems. In turn, those will produce better results than not calibrating your monitor at all.
Whichever method you use, the result will be a profile of your monitor with those settings. The next time you launch Photoshop, it will use your newly created profile. Do not change the settings on your monitor after you profile it — specifically do not change brightness, contrast, or color settings. If you do change settings or significantly change the lighting environment, you should repeat the profiling process.
The built-in screens of laptops are not ideal for obtaining good color matches with prints.
- Good color management requires a monitor that has been profiled; its controls must be set the same way as when the profile was created. Laptop screens can be more non-uniform (with different color and brightness in different parts of the screen) than high-quality desktop monitors, and they are set very bright and/or with brightness automatically varying based on the ambient light. That is great for web browsing in bright light and coffee shops, but your prints will always look dark — or worse, sometimes OK, sometimes a little too dark, and sometimes far too dark.
Make sure you have profiles for the printer and paper combinations you’ll be using
(do this when you first start using a new kind of printer paper)
- Most inkjet printers today — especially ones meant for imaging rather than business use — come with reasonably good profiles for various types of paper made by the printer manufacturer, and those profiles are installed along with the printer software. If you’re using a new kind of paper, or a paper that isn’t made by the printer manufacturer, you will have to obtain a profile from the paper manufacturer’s website or another source.
Do not use cheap ink in your inkjet printer
- Inkjet ink is expensive — but for low volume, high quality printing there is no easy budget alternative to the printer manufacturer’s ink. Save budget replacement ink for word processing documents and spreadsheets with graphics. For color accuracy and consistency, use either the printer manufacturer’s ink or specialty imaging ink such as that made by Lyson (use of specialty ink will also require custom profiles — a printer profile is specific to the combination of printer, ink, and paper). Inexpensive store brand inks carry a high risk of poor and variable color results and significantly lowered print longevity.
Prepare a lighting environment near your monitor for viewing prints
(do this once when you set up your computer workspace).
- You need a space near your monitor that has light suitable for viewing the print — preferably similar to the light in which it will eventually be viewed, and preferably near the monitor so you can look from one to the other. Generally that won’t be direct sunlight (which would make it hard to see your monitor anyway), and it won’t be pitch darkness (which might be tempting for viewing your monitor, but then you can’t see your prints). It’s often best not to hold the print up right next to the monitor because if there’s good light for print viewing in that position, there’s probably light reflecting off the monitor, which is bad. On the desk to one side is ideal.
No matter what you do, your prints will never match your monitor exactly, because:
- The monitor is emitting light and the print is reflecting light.
- The print will look somewhat different depending on the light in which it is viewed: it will look different under incandescent light, indirect sunlight, and fluorescents.
- The monitor and the print can’t represent all the same colors nor the same range of brightness from light to dark. For example, the monitor can likely produce some deep blues and reddish-purples that your printer can’t print — especially if you’re printing on matte paper. The monitor can show a hugely greater brightness difference from black to white than can the printer (again, especially if you’re printing on matte paper). The printer can probably print middle tone and deep blue-greens and greens that the monitor can’t display. The color management software modifies many of the colors in the document to provide the best overall result on each device. It doesn’t just take the colors that are too saturated to represent on a particular device and replace them with the closest color that can be shown. That would eliminate all detail in colors near the extremes of the device’s capabilities. Instead, it shifts many colors subtly to preserve overall appearance.
Use soft proofing to get a better idea of what your print will look like
(do this as desired, or each time before you print)
- If you’ve calibrated your monitor, what Photoshop is showing you on the screen is the most accurate representation possible of your document. If you then print that document using an appropriate profile, it will print the most accurate representation of your document that the printer can print. Because of the factors listed above, those will usually be quite different.
To see a soft proof of your document, choose View > Proof Setup > Custom and set the dialog items as follows:
- Device to Simulate: Pick the profile for the printer and paper combination you want to proof.
- Preserve RGB Numbers: Deselected
- Rendering Intent: Perceptual or Relative Colorimetric (you usually won’t see much difference between these, but the one you choose should match the one you pick in the print dialog when you print the document)
- Black Point Compensation: Selected
- Simulate Paper Color: Selected
- Simulate Ink Black: Selected
Then click OK.
This prepares settings for this particular paper and printer combination and turns on soft proofing. To toggle soft proofing for this setup on and off, choose View >Proof Colors. You can perform any editing operation while soft proofing is on.