Soft proofing

Wouldn’t it be great if you could make the image you print look exactly like the one you see on your monitor screen? Technically this is a big ask. Printing an image reduces its inherent contrast and dynamic range. On very glossy paper stock using the blackest possible ‘photo’ ink, you might achieve a contrast ratio of 300:1. With matte papers, a 200:1 contrast ratio is more realistic.

Most LCD screens have native high contrast ratios of 1000:1, which is three to five times the contrast ratio of prints. And monitor manufacturers often boost contrast to make displays more attractive for playing video games or viewing video content. This makes the screen unsuitable for printing.

Provided you use a monitor with normal contrast, soft proofing can provide a way to simulate how the image will appear when printed. While the technique doesn’t overcome the inherent contrast differences between the screen and the printed image, it does help you to produce more predictable prints. But it requires a trained eye, plus some knowledge of how to correct an image if it doesn’t appear as intended.

Initial requirements
You can carry out soft proofing with most image editors, provided they contain the tools needed for adjustments and support for ICC profiles. We’ve used Adobe Photoshop and Photoshop Lightroom for this demonstration because they are popular with photographers.

You also need a calibrated and profiled monitor and ICC profiles for the printer and papers you plan to use. Ideally these should be custom profiles that have been measured for your particular printer, ink, paper and driver settings. If you don’t have a colorimeter that can measure paper, simply use the printer manufacturer’s ‘canned’ profiles ““ making sure you select the correct profile for the paper and ink combination.

Monitor calibration
If you’re not working on a calibrated monitor, you can’t expect consistent and accurate results when  printing your photos, either at home or through a lab. The best way to calibrate a monitor is with a device called a colorimeter. Entry-level colorimeters are available for around $250, with more sophisticated units that can also be used for paper profiling priced at around $650.

The calibration process is straightforward. The colorimeter is positioned on the surface of the screen and measures the light emitted by the display as it projects a sequence of colour patches. Software calculates the numerical difference between the each of the pure colour values and the values displayed by the screen and uses this data to calculate a ‘profile’ for the screen.

This profile can be used to share information between devices within the imaging workflow in order to achieve consistent colour reproduction at each step. Profiles created for monitors are stored in the computer, where they can be accessed for use with paper profiles to ensure colour consistency.

A colorimeter makes it easy to create profiles that can share colour information between devices to produce accurate colour reproduction throughout the imaging chain.

Soft proofing in Photoshop

Open the image you plan to print, make the necessary adjustments and then click on View > Proof Setup > Custom.

The controls used to produce a soft proof.

From the dialog box make the following selections:

A: In the Device to Simulate dropdown menu, choose the profile that corresponds with the paper you plan to print on.

B: From the Rendering Intent dialog box, select  Relative Colorimetric. This rendering compares the extreme highlights of the source colour space to those of the destination colour space and shifts all colours accordingly. Out-of-gamut colours are re-mapped to the closest reproducible colours in the destination space, which preserves more of the original colours in an image than the Perceptual setting. Make sure the Black Point Compensation  box is checked.

C: Check the Simulate Paper Colour box. This maps the white point in the profile to the base colour of the paper you are using. Leaving it unchecked maps the white point to the maximum white of the monitor and won’t replicate the actual white of the paper.

D: Check the Preview box to see the soft-proof applied. Click on OK to apply the soft-proof.

Note that none of these adjustments will change the image itself. Soft proofing is not editing.

Clicking on OK closes the dialog box and returns you to your image. You can switch between the soft proof and the original image with the Ctrl+Y buttons in Windows or Command+Y on a Mac.

It’s a good idea to rest your eyes by looking away for 20-30 seconds each time you change between the proofed and unproofed views. In most cases, the differences between them should be quite subtle. (If they aren’t you should print a test strip before committing to printing a whole A3 or larger page.)

Soft proofing in Lightroom

Lightroom uses the same controls as Photoshop but they are handled differently. Open the image in the Develop module and select the Soft Proofing box in the toolbar below the image. The preview background will turn white and a Proof Preview label appears in the upper-right corner of the preview area. The Soft Proofing panel also opens.

Opening the Soft Proofing panel in Lightroom. The Soft Proofing check box is circled in the toolbar below the image.

Apply the following settings in the Soft Proofing panel:

1. Choose the printer and paper profile you would like to soft-proof.

2. Select the Rendering Intent in the same way as outlined for Photoshop.

3. Check the Simulate Paper & Ink box.

There are two tiny icons in the top corners of the histogram. The one on the left is the Show/Hide Monitor Gamut Warning, which causes colours that fall outside the gamut of your monitor to appear blue in the image preview area. The one on the right is the Show/Hide Destination Gamut Warning. Clicking on it causes colours that fall outside your printer’s rendering capabilities to appear red in the image preview area. Colours that are outside the gamut of both the monitor and the printer will appear pink in the image preview area.

If you want to edit the image to bring it within a desired colour space, click Create Proof Copy. Lightroom creates a virtual, editable copy of the image that you can tweak before printing.

Article by Margaret Brown –  see Margaret’s photography pocket guides  

Excerpt from  Photo Review Issue 69      

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