Test Strips and Proofing Options

If you are forced to print with an uncalibrated monitor and rely on a non-colour-managed workflow, you can waste a lot of ink and paper. However, there’s an easy way to minimise the amount of paper you use to check the image will print correctly: make test strips. Here’s how to go about it.

Step 1: Edit the image in your favourite software application and save it separately at the correct output size – either in a special ‘printing’ folder or with the tag ‘for printing’ added to the file name. If you want white borders, this is the time to use the Image > Canvas Size setting to position your image on the page. In the example shown, the image size is 19 x 25.33cm, which fits on an A4 sheet with a narrow white border. To place it on a canvas size of 32.9 x 48.3cm (A3+ size), simply change the New Size Width and Height to 32.9 x 48.3cm.

Step 2: Using the Crop tool, select a strip that runs through a critical area of the image where you want detail to be fully resolved. The strip should be rectangular but it can be almost any size you want – as long as it covers the key ‘exposure’ area. Do not change the size of the image as this could change the print quality. (There is no need to save the ‘test strip’ unless you wish to use the same area subsequently. If this is the case, tag the file name with ‘test’.)

Step 3: Load the printer with a sheet of the paper you will use for your final enlargement and re-set the paper size and orientation accordingly. Open the printer driver and set the paper size and orientation to match the paper you’re using. Then return to your software application and select Print. Uncheck Centre Image and use the Position settings to position your test strip on the sheet of paper.

Step 4: Print the test strip using the settings you will use for the final print. Now assess the test strip, checking colour, brightness, sharpness and any other adjustable parameter that is relevant. Make the required changes to the saved image file and, if you wish to check them again, get ready to make a second test strip on the same sheet of paper as you used for the first.

Step 5: Repeat the steps above until you reach the point where you position your second test strip. Use the Image > Image Size control to see how large your cropped test strip is (re-crop it if necessary to ensure it fits on the sheet of paper). Measure the distance from the top (or side) of the page and adjust the Position settings to make the second test strip fit in either below or beside the first one.

Step 6: Load the paper in the printer again so the second test strip is correctly printed. (Most printers work from the top of the page downwards, which means you should load the paper top-downwards.) Print the second strip and evaluate it as outlined above.

With care, you should be able to fit between four and six test strips of a suitable size for making A3 prints on a single sheet of A4 paper. The illustration below shows a typical example.

Success depends on accurately measuring and setting the correct position for each successive strip – and remembering to orientate the paper correctly each time you make a print. (If you’re using an Epson R800 or R1800 printer, turn off the Gloss setting to prevent an excessive build-up of resin on the surface of the paper when making test strips.)

When you have a test strip you’re happy with, use the Page Setup function in the File menu to set the paper size and orientation to match the output size for the final print. Then open the image, adjust it to the correct size for printing and centre it on the page.

You may need to refer to the printer driver page to match the image Document Size to the Scaled Print Size. Checking the Scale to Fit Media box in the printer driver will ensure your picture fits the paper and is placed centrally on the sheet.

Soft Proofing
Photographers who edit images with Adobe’s Photoshop software can take advantage of its Soft Proofing facility, which provides an accurate on-screen preview of how the image will print. Unfortunately, this facility isn’t provided in Photoshop Elements and it’s only usable in a colour managed workflow as it relies on ICC profiles. How well it works depends on qualities in the image, the paper/ink combination and the effectiveness of the profiles (and your calibration system).

Step 1: Make sure there are no images open on the Photoshop desktop then select View>Proof Setup>Custom.

This opens a Proof Setup dialog box with three drop-down menus: Profile, Intent, Simulate.

From the Profile menu select the profile of the paper you plan to use.

Set the Rendering Intent to Relative Colorimetric or Perceptual and check Simulate Paper Colour in the Display Options box. Leave Preserve Colour Numbers unchecked.

At this point you can save the preview profile for use with subsequent image files by clicking on Save. Give your profile a relevant name that allows you to identify the printer and the media the profile has been created for. Click on OK and return to the Proof Setup menu where you’ll see the new profile has been added to the end of the list.

Step 2: Open the image you plan to print and select Image>Duplicate. This will create a second copy of the image. Align the two images so they appear side-by-side on the desktop.

Select the original image then click on View>Proof Setup and choose the soft proofing profile you created from the drop-down list.

Then click on Proof Colour in the View menu. This will probably cause some subtle changes to the original image, relative to the duplicate because the software is attempting to replicate the characteristics of the paper. The image will probably look flatter or less contrasty and there may be subtle hue or saturation shifts. These changes will replicate how the image will look when it is printed on the selected paper with the nominated printer.
Step 3: If the changes to the original image are greater than you can tolerate, you may wish to edit the image, using the duplicate as a reference. Start by selecting the original and then select Layer>New Adjustment Layer and choose the editing tool you wish to use. (We’ve selected Vibrance for this image as it also allows you to adjust colour saturation. You may wish to adjust Levels, Curves or some other parameter).

Once you’re satisfied that the edited original looks the same as the duplicate reference, you can print the image.

Unprintable Images
Printed images usually look much ‘flatter’ than images viewed on-screen. Consequently, some images that look great on your monitor may not look as good when printed as they do on your monitor because of the differences in dynamic range between images viewed on a backlit screen and output on paper. The wider the dynamic range, the better the media will be able to reproduce differences in scene brightness.

Although a good monitor can have a dynamic range in excess of 15,000:1, the dynamic range of photographic prints tops out at 100:1 and, within that range, the normal human eye can only distinguish between 100 and 200 distinct luminance levels. In addition, certain highly-saturated colours are beyond the capabilities of current inks.

If you really want to print images with wide dynamic ranges, try using a tool like the Shadow/Highlight adjustment setting (found in both Photoshop and Photoshop Elements). It allows you to bring up details in dark areas while suppressing over-bright areas. The result may be a printable image; but be wary of making dramatic changes to either setting as posterisation can result.

The Shadow/Highlight adjustment tools can be used to brighten the shadowed areas on the camel and rider.

The result of the adjustment with the Shadow/Highlight tool in Photoshop Elements 7.

Printing Multiple Images
A handy way to reduce printing costs is to print several images on the same sheet of paper and then cut the paper to make separate prints. There are many printing applications that enable you to do this. Most printer manufacturers supply suitable layout programs as part of the bundled software suite.

The layout programs supplied with most photo inkjet printers usually include multi-image layout settings.

Many editing programs also include multi-image layouts. For example, Adobe’s Photoshop Elements includes a Print Multiple Photos setting in the File menu that allows you to select images from the Catalog, choose a layout and add decorative elements, if required.

Corel’s MediaOne Plus provides templates for scrapbooking layouts and you can find numerous other applications (including freeware and shareware) by doing a Google search on scrapbooking. If you need a more sophisticated application, Qimage (www.ddisoftware.com/qimage) is a worthwhile choice as it provides ICC profile support. It’s compatible with a wide range of printers and includes a panorama printing facility for printers that can work with roll paper.

How to ‘Read’ the Ink Usage Graphs
Many inkjet printers produce a graphic display to show the levels of ink in each cartridge so users can see when the ink is running low. Some will alert users when ink levels are low, usually when less than 20% of the ink remains. You can usually keep on printing until less than 5% of ink remains in a cartridge.

The Photo Black and Yellow cartridges are the closest to running out on this printer but enough ink remains to continue printing. This display reminds you to have replacement cartridges on hand but is not an indication to replace the cartridges immediately.

In most cases you can get at least three or four extra A4-sized prints after this warning has been displayed. With practice, you will learn to estimate just how much ink remains and the area of paper it will cover. Many printers will cease operating when the ink in one cartridge runs very low. If yours doesn’t, a change in the print colours part-way down the print will indicate a depleted cartridge.

Replace the cartridge and insert a new sheet of paper before you continue printing. You will probably need to wait for a minute or two while the printer prepares the new cartridge for use.

Dynamic Range Compression
Prints never look quite as good as the image on the monitor because the dynamic range of paper is very much less than that of a computer screen. For example, a typical MCD display could have a dynamic range as high as 600:1, whereas papers can only reproduce 200:1 at the most. Printer profiles for each paper include the DMax (maximum density – or deepest black) and DMin (brightest white) for each paper type.

In properly colour-managed workflows, these figures are used to calculate the degree to which the dynamic range of the digital image must be compressed and how the image tones are translated into the dynamic range of the paper used for printing. This compression is largely responsible for the apparent differences you see on your screen when comparing the original and proof images in soft proofing mode.

Assessing Print Quality
When you make the first print in a printing session, be sure you examine it carefully. Here are some things to look for:
1. Fine (or not so fine) track lines across the print surface that indicate uneven ink deposition. Initiate a head cleaning cycle and re-do the print if this occurs.

2. An uneven surface texture. This problem is called ‘bronzing’ and indicates that ink has been unevenly deposited and/or absorbed by the paper. Cleaning the print head and reprinting the image may solve the problem but some ink/paper combinations are inherently prone to this fault. Try changing to a different paper for your reprint.

3. White patches on the surface of the image. This usually indicates dust on the paper surface before the print was made. Re-print on a clean sheet of paper – and take more care with storage and handling of media.

4. Prints that are consistently too dark or too light or off-colour indicate your monitor is not calibrated to match your printer’s output. Recalibrate the monitor and make test strips until the print you make matches the image you see on the screen.

5. Low ink density in one or more colours can indicate a depleted cartridge or blocked nozzle. Most photo printers will not print if either of these problems occur.

If you plan to display your prints under artificial lighting you should also check how the print will look under the actual lighting conditions in which it will be displayed. You may need to make some slight adjustments to brightness, contrast and colour balance to ‘optimise’ the print for its viewing situation.

USEFUL URLs
The following websites provide additional information on the topics covered in this chapter.

www.computer-darkroom.com for some excellent tutorials on colour management and soft proofing and articles on using Adobe software.
www.luminous-landscape.com for a series of ‘Understanding’ articles that includes soft proofing, colour management, colour theory and many other topics.
www.adobe.com/designcenter/tutorials/ for step-by-step tutorials on new features, key workflows, and advanced techniques with Adobe software.
www.apple.com/ilife/tutorials/#iphoto for tutorials on the various aspects of iPhoto.
www.photoreview.com.au for articles on digital printing and printer reviews.

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