Building a Scanner Profile

This article references MonacoEZcolor from Monaco Systems (www.monacosys.com) to illustrate the process of creating a scanner profile. MonacoEZcolor provides a very easy-to-use package for creating monitor, scanner, and printer profiles. It supports both Microsoft® Windows® and Macintosh operating systems, and it sells for less than U.S. $300. The software by itself doesn't include everything you'll need for all of these purposes; for example, it doesn't include a sensor for creating monitor profiles. It does, however, include IT-8 targets for creating reflective and transparency profiles for flatbed scanners. To create a custom profile for a film scanner, you'll need to purchase a 35mm IT-8 target, which is available from Monaco Systems for about $40.

Figure 2

Follow these steps to create a custom scanner profile using MonacoEZcolor:

1. Launch MonacoEZcolor.
2. Select the type of profile you would like to create (see Figure 2). In this case, you should select Create Input Profile because a scanner is considered an input device.

Figure 3

3. The Before You Begin screen provides some important reminders (see Figure 3). Be sure that the scanner you will be profiling has been turned on for at least 30 minutes to ensure it has stabilized. The Before You Begin screen also reminds you to turn off the automatic adjustment options provided in the scanner software and to turn off any color management options. Review the reminders, and click the Next button (the right arrow) to continue.
4. In the Select Target Type window, select the type of IT8 target (see Figure 4) you will be scanning to produce a profile. For profiling a flatbed scanner for prints, you will select the 5x7 Reflective option. For a flatbed scanner while using a transparency adapter, you will select the 4x6 Transparency option. If you are profiling a dedicated film scanner, you will use the 35mm Transparency option. Click Next.
5. In the Position the Target window, you'll find guidance for scanning the IT8 target for the type of scanner you are profiling. For flatbed scanners, be sure the glass is clean, and then place the target on the glass. If you are using the transparency target for your flatbed, be sure it is aligned under the area that the transparency adapter actually illuminates. For film scanners, insert the 35mm target into the scanner as you normally would to scan a slide. Encarta automatically adds a copyright notice to the picture.
6. If your scanner supports TWAIN, click Twain Acquire to directly scan into the MonacoEZcolor software. Otherwise, click Load An Image. The TWAIN option is preferable, as it avoids any possible application of other profiles, such as your working space, when you scan the image and save it using your image-editing software. If you decide to load an existing scan, skip to Step 10.
7. MonacoEZcolor will attempt to launch your scanner driver (perhaps launching Photoshop or another image-editing application, depending on how your system is configured). Adjust the scanner settings using the resolution recommended by MonacoEZcolor in the previous step. Reset all controls to their neutral values, and turn off any automatic adjustment or color management options.

Figure 4

8. Crop the target so it is the only item being scanned, and click the Scan button to acquire the image. Close the scanner software when the scan is complete.
9. Verify the scan to confirm it is properly cropped and oriented. The screen displayed will show a thumbnail of the scan you created, along with a series of samples showing you a good scan and examples of incorrect scans (see Figure 5). If your scan is not correct, click the Back button (the left arrow) and rescan the target. Otherwise, click Next.
10. In the Select Reference File window, choose the appropriate reference file for the target you are scanning. This information is shown on the target itself. Click the Select Reference button, choose the appropriate reference file, and click Open.

Figure 5

11. Click the Save Profile button, and type a name for the profile you have created. You may want to name the profile to reference the specific scanner you are using, as well as the type of profile (reflective or transmissive), if you are profiling a flatbed scanner.
12. The final dialog will confirm that the profile was successfully created. Click Next to return to the Welcome screen from Step 2.

Integrating Profiles with SilverFast

SilverFast is specialized scanning software from Lasersoft Imaging (www.silverfast.com) that provides exceptional control over the scanning process. It supports a wide variety of scanners and is particularly useful for those who want to produce the best scans possible. In addition, an option is offered that allows you to create custom profiles for your scanner using a standard IT-8 target. SilverFast even allows you to apply that custom profile directly to the scan, which is very convenient. Pricing for SilverFast varies with the particular scanner supported, but for a typical film scanner the price is less than $350, including an IT-8 target for profiling.

Assigning a Scanner Profile

Figure 6

A custom scanner profile provides the information needed to translate the data from your scans into accurate color information in the image file. However, that translation doesn't happen automatically, because most scanning software doesn't allow you to assign custom profiles directly to your images. Instead, you'll have to assign the profile to the file after opening it in your photo-editing software.

The color value for each pixel in an RGB image is stored as values of red, green, and blue that together define the exact color of the pixel. However, by themselves these values don't mean anything; they are just numbers. To assign a color to them, a translation table must define what the values mean in a device-independent color space. In the absence of a profile, the colors will be interpreted by Photoshop based on the current RGB working space.

Obviously, that RGB working space does not accurately represent the color values in our scanned image. That's why you created the custom profile. All you need to do is tell Photoshop to translate the color numbers in your image based on the translation information in the custom scanner profile that was used to scan the image (see Figure 6).

Understanding the difference between assigning your custom scanner profile to the image and converting the image to that profile is important. Assigning a profile does not cause the color values in the image to be changed. Rather, it causes them to be interpreted based on the information in that profile. The colors remain the same, but their meaning changes.

Figure 7

Converting an image to a profile is very different. Instead of changing the way the color values are interpreted, it changes the numbers in the image data file so that each pixel will have the same color appearance (as closely as possible) when interpreted based on a different profile. When using a custom scanner profile, you most certainly don't want the colors in your inaccurate scan to remain the same. This is why the custom scanner profile will be assigned to the image, rather than converting the image to that profile.

In order to obtain the best results, it is important that the color values in the original scan do not change before the custom profile is assigned. If you are opening a scanned image, it is therefore important that you do not allow the image to be converted to your working space when it is opened. In Photoshop's Color Settings dialog box, click the Profile Mismatches: Ask When Opening and Missing Profiles: Ask When Opening check boxes to ensure that images are not automatically converted to your working space. Otherwise, in the RGB: list, select Preserve Embedded Profiles.

Figure 8

To assign your custom scanner profile to an image, complete the following steps:

1. Click the File menu, and then click Open to open the image. If the Missing Profile dialog box is displayed, select Assign Profile (see Figure 7). Select the appropriate profile for your scanner from the list. In most cases, you also should select the Then Convert Document to Working RGB check box. Click OK, and the profile will be assigned to the image. You can then skip the rest of the steps here.
2. If the Missing Profile dialog box was not displayed, click the Image menu, point to Mode, and click Assign Profile (see Figure 8).
3. Select Profile.
4. From the drop-down list of profiles, select the custom scanner profile you created for the scanner that was used to scan your image.
5. Click OK. The colors in the image will now be interpreted based on your custom profile.

Due to problems caused by the "orange mask" included in the emulsion of negative film, it is not possible to produce reliable profiles for scanning negatives. For those images, you'll need to use the settings in your scanning software to produce the most accurate results.

Remember that in order to ensure the most accurate results possible, whenever you scan an image that will utilize a custom scanner profile, your scanner settings should exactly match the ones you used when scanning the target during the profile creation process.