how-to-calibrate-for-it8

How To Calibrate for IT8

The first step to calibration is getting a scan of your IT8 card. If you have gone through the software part of the guide, you should be able to use Canon, Epson, or Vuescan scanning software to get a “flat” RAW scan of your card. 400-600DPI is recommended as the calibration software sometimes has issues with high resolution scans at 800DPI or higher. Make sure you don't use any kind of TIFF compression (This is default behavior) when saving your scan as that will cause it not to be able to open in the calibration software. Crop around the card so there’s no white space. If you crop into the card a bit it’s okay as long as it’s within the initial grey border. Also make sure when you're scanning the card that you remove it from the protective sleeve, as some people have scanned it while it was still in the sleeve which you don't want to do.

The biggest key to calibration is to scan your IT8 target in exactly the same way you plan to scan your boxes/manuals etc. So if you’re planning on using Epson Scan and scanning in 24-bit, you’ll need to scan your IT8 target with the exact same settings. If you’re planning on doing 48-bit as well, then you’ll need to scan and calibrate separately for that. It’s really up to how you want to do it. For most users having a single calibration file will be all that’s needed because you’ll likely always use the same settings and software when scanning.

Your RAW scan of the IT8 card should look similar to this image:

r181224.jpg

Now that you have a scan of your card you need to run it through calibration software, and our recommendations will differ depending on your operating system but they all use the same calibration software underneath the covers: ArgyII CMS.

Our recommended GUI Windows solution is a software called CoCa. It's fairly easy to use and produces great profiles! So go ahead and download and install that. You'll also need to download and unzip the ZIP file tied to the Charge Number in the lower right corner of your IT8 card if you ordered it from our recommended vendor. Scroll to the bottom of that page and look for your charge number, and download and extract the ZIP file. You'll need the .txt file with the same Charge Number from this for calibration. Now go ahead and start the CoCa software and it will look similar to this.

Now let's go over each section and what you should do in them:

Target Image - Click the select button and browse for the scan of your IT8 card and select it.

Reference File - Click the Custom button in this section and browse to the place you unzipped the Charge file ZIP you downloaded earlier. Select the .txt file with your charge number that should be located in the extracted folder from the ZIP file. For example if your card says R181224, the file will be called “R181224.txt”.

Profile Information - Optional but I recommend filling this out with descriptive information, especially if you are going to do multiple profiles (say one for 24-bit and one for 48-bit.) The field that you'll actually see when you go to select your profile is the Internal Profile Description. You can see in the example that we added the Scanner Model, the software used (Epson Scan) and the bit depth. We recommend doing something similar.

Corrections - You shouldn't need to adjust this unless you scanned your IT8 card in Vuescan in 48-bit RAW mode. If you do that your scan will be VERY dark and that means your Gamma is 1.0. You'll need to change the Gamma from 2.2 to 1.0 if you did that, otherwise leave it at 2.2.

Select Target Type - Pick IT8.7 here.

Options - Select Display XYZ cLUT + matrix as your algorithm, for Default Intent we pick Absolute Colorimetric as we commonly use that when converting images to SRGB, but Relative is fine here too. Quality should be set to High.

After you've set your options correctly click the Create Profile button. You'll see a black box pop up and it will start the calibration process. Once it's finished if everything went okay you should get a Save dialog box. Make sure you save your profile to C:\Windows\System32\spool\drivers\color as that's where Windows looks for IT8 profiles. Once that is finished you're done and you now have an IT8 profile you can attach to your scans in your image editing program of choice. Congrats!

Our recommended Mac & Linux solution is a software called ArgyII which you can download and install for Mac or for Linux. You'll also need to download and unzip the ZIP file tied to the Charge Number in the lower right corner of your IT8 card if you ordered it from our recommended vendor. Scroll to the bottom of that page and look for your charge number and download and extract the ZIP file. You'll need the .txt file with the same Charge Number from this for calibration. Now open up a command prompt and browse to the directory where you have stored your RAW IT8 scan and the .txt file.

Run the following command:

scanin (your-it8-scan).tif it8.cht (charge-file-number).txt

That should output a .ti3 file that should have the same name as your TIF file, you'll use this in the next step.

Next, run the following command:

colprof -D

If all goes well that should output an ICM file in your Argy folder and you now have your IT8 profile! Congrats!

If you have a Mac you want to place it in /Library/ColorSync/Profiles/ for it to show up in your image editor of choice.

For Linux it's usually placed in one of these places -

/usr/share/color/icc

/usr/local/share/color/icc

/home/USER_NAME/.color/icc

If you placed you IT8 profile in the correct folder it should now show up in image editing programs and you can attach it your scans. Below are directions for GIMP and Adobe Photoshop.

Open your image and then go up to Edit on your toolbar then Assign Profile.

Check the dot next to Profile: and then find your IT8 profile here and click OK.

That is it! You should now see your scan color corrected. Save it as either a TIFF (If 48-Bit) or PNG (If 24-Bit) and you are done. Remember that a lot of programs (Including Web Browsers) won't display IT8 profiles but if you see it in your image editor it is there and correct. So don't freak out if you don't see it when you view it on the web.

Open your image file in Gimp and navigate to Image - Color Management - Assign Color Profile

After clicking that a dialog box will appear. Click Assign and the browse for the ICM file to assign to your scan. After that is selected select Assign.

That is it! You should now see your scan color corrected. Save it as either a TIFF (If 48-Bit) or PNG (If 24-Bit) and you are done. Remember that a lot of programs (Including Web Browsers) won't display IT8 profiles but if you see it in your image editor it is there and correct. So don't freak out if you don't see it when you view it on the web.

  • how-to-calibrate-for-it8.txt
  • Last modified: 2021/03/23 22:29
  • by hubz