As film shooters, we all want to create accurate scans of our film. Vuescan is one of the most powerful scanning softwares available today. Ed Hamrick does a great job keeping the software up-to-date.
Creating accurate ICC profiles for your film is very important to achieve correct colour reproduction. Unfortunately Vuescan does not do a very good job of creating or embedding ICC profiles. The following is a best-practices of how to achieve the most accurate scans from Vuescan. This process is a collaboration between many people, including Martin Jericho and Wolf Faust.
There is a very good chance you will have to repeat this process a few times to create the best profile for your film. Be patient with the process, it’ll be worth it in the end.
This process of profiling and scanning with Vuescan was originally published on my personal blog, blog.iansheh.com. The information on this site has been revised from the original post with additional information from the various contributors and commenters.
The process below is specific to profiling slide film. It should work with targets specific to photographic paper, but has not been tested.
Scanning IT8 Target
The IT8 colour chart is an international standard designed to communicate and control colours. An IT8 target is the media (film, paper) that the chart is produced on in which a profile is created from. The idea in this step is to capture the best exposure of your IT8 target to ensure accurate reproduction of colours from your scans.
1. Connect and turn on your scanner
2. Open Vuescan, and change the following settings:
• Set Task to Scan to File
• Set Source to the scanner you are using
• Set Mode to Transparency
• Set Media to Slide Film
• Set Resolution to at least 2000dpi
Filter Tab: (if your scanner supports this function)
• Infrared Cleaning: Light
• Color Balance: None
• Curve Low: 0.25
• Curve High: 0.75
• Set all Brightness values to 1
• Slide Vendor: Generic
• Slide Brand: Color
• Slide Type: Slide
• Scanner Color Space: Built-in
• Printer Color Space: ProPhoto RGB
• Film Color Space: Built-in
• Output Color Space: ProPhoto RGB
• Select Raw File
• Raw File Name: Reference the film you are scanning followed by a unique identifier (number or letters)
• Raw Size Reduction: 1
• Raw File Type: 48 bit (or 24 bit, depending on your scanner)
• Raw Output With: Save
• Raw Save Film: Not Selected
• Raw Compression: Off
• Raw DNG Format: Not Selected
3. Scanning your IT8 film target
• Click Preview to capture an initial view of your IT8 target • Make a Selection around the IT8 target, leaving a little bit of grey around it. • At the bottom of the Input Tab select Lock Exposure
• Write down the RGB Exposure value – you will need to reference this value later in the process
• Click Scan to create your IT8 film target scan
Reference Screen Shots
• Vuescan’s RAW file format is not the same as your camera RAW files (CR2, NEF, RAF). Vuescan’s RAW is essentially a TIF file with additional data enabling you to re-process the file in Vuescan without re-scanning your film. As a TIF file, Vuescan’s RAW format does not afford you the same adjustments – exposure, white-balance, tone, sharpening, etc. – as a camera RAW file would. This applies to Vuescan’s DNG file format as well.
• Setting the curve values to 0.25 and 0.75, respectfully, creates a straight curve.
• Adjusting the curve values will directly affect your scans, and can be used to adjust low/high detail. Decreasing your low value will increase shadow detail. Increasing your high value will increase your highlight detail. This is a hardware adjustment, and results will rely on your particular scanner.
Create ICC Profile
In this step we will be creating the ICC profile from the specific IT8 film target you have scanned, and placing the profile in your system. We are using Rough Profiler to create our profile.
1. Open Rough Profiler, and change the following setting:
• Preset: None
• Chart Type: IT8.7
• Reference File: Select the reference text (.txt) file that accompanied your IT8 film target
• Test Chart: Select the IT8 film target scan you created
• Gamma: 1.0
• Quality: Medium
• Force cLUT Absolute: None
• Algorithm: XYZ cLUT
• Profile Name: Reference the film & scanner (if you have multiple scanners) in your name
• File Name: Use the same name as your Profile Name
• Model: Should automatically be filled in
• Manufacturer: Should automatically be filled in
2. Click Create Ti3
• Once complete, your IT8 chart should now be outlined
3. Click Create ICC
• Your ICC profile will be saved to the same folder as your IT8 target scan. Three files will be created: ICC profile, Ti3 data, and daig.tiff file.
4. Placing your ICC profile into your system
• Open the Finder
• Select the Go menu, and hold down the Option key
• Select the Library folder once it appears on the menu
• Open the ColorSync folder
• Open on the Profiles folder
• Create a new folder called Film
• Place the ICC profile you created in the Film folder
• Right Click on the ICC profile you created
• Select Install Profile
Reference Screen Shots
• IT8 reference text files: If you purchased your target from Wolf Faust, and have lost the text file, he as a library of reference files online. You will have to match the number of your target to the number of the text file.
• Creating a Film folder to store all of your profiles is an organizational step, and not necessary. The folder will not show up in Photoshop.
Assign ICC Profile
Here we are going to assign the ICC profile you created to the IT8 film target you scanned. This will allow you to evaluate your initial IT8 target scan and determine if you need to adjust the RGB Exposure in Vuescan when scanning.
1. Open Photoshop, and open your IT8 film target scan
2. Assigning the ICC Profile
• Select the Edit Menu
• Select Assign Profile
• Select Profile – Find the ICC profile you created
• Press Ok
3. Converting Color Space
• Select the Edit Menu
• Select Convert to Profile
• Select Destination Space Profile
• Select either AdobeRGB or ProPhoto RGB
• Press Ok
4. Evaluating the IT8 target scan
• To evaluate your IT8 target scan and determine if the RGB Exposure in Vuescan is correct, we will examine the first white box in the gradient at the bottom of the chart.
• Open the Info tab
• Zoom into the bottom left corner of the chart
• Select the Eyedropper Color Sampler Tool
• Click in the middle of the first white box to determine the RGB values
• The RGB values should be within the 240-250 range. Values closer to 255 are too high, and will cause highlight clipping. Values under 240 can cause the target to be under exposed.
• It is important that your IT8 scan is exposed properly. Increasing your IT8 scan to the highest exposure before clipping will produce the most shadow detail.
5. If your RGB values are not within the 240-250 range, repeat the process.
• In Vuescan, adjust your RGB Exposure value by +/-0.05 from the initial value you wrote down
• Rescan your IT8 film target
• Creating a new ICC profile
• Assign the profile your new IT8 scan and evaluate the RGB values.
Reference Screen Shots
Once you have created an ICC profile to your satisfaction, you are ready to scan and profile your film. The process is similar to creating the profile.
• Scan your film with the same settings you used for the IT8 film target.
• Set the RGB Exposure value to the same value used to create your ICC profile.
• Change the Output Tab File setting to the destination folder you would like to save your scans to.
• Open your scan in Photoshop, assign your profile, and convert the color space.
To make the process of assigning an ICC profile and converting the color space easier, create an action in Photoshop for each profile. Run a batch process on all of the scans you need to assign the same profile to.
Profiling your film will provide the best starting place for editing your images. Even with a proper ICC profile, your image may not appear as it does in your minds-eye. There are many variables that will affect how the film will reproduce colours: type of film (Kodak biases red/orange, Fuji biases green/blue), the time of day, the temperature of the light source, the lens, as well as the scanner used. When taking your film to a professional lab to be scanned, each lab tech will have a different bias on colour as well. You may find that one particular lab tech produces colours more to your liking.
With all good starting places, you now have a solid base to adjust and play with this process. Maybe your ideal image is slightly cooler than your scanner/profile produces, you can reduce the Red Analog Gain in Vuescan to produce a colder tone.