Nuclear Light - The Color Solutions

FireGrade User Manual





Installing the plugin


Using the plugin





Each photographer or designer needs to do color correction from time to time as part of their job. Sometimes the task is very complicated. Sometimes it is simple but tedious, and takes a lot of time. Sometimes you know what you need to do, but don’t know how to do it. And sometimes you are so overwhelmed by correction layers, layering modes, and third-party software, that you forget what you wanted to do in the first place. FireGrade, our reliable and user-friendly plugin for Adobe Photoshop, will help you do color correction in a nice and easy way. Now you can leave all that annoying stuff behind and quickly color-correct images within Photoshop.


FireGrade internally works in the Lab/Lch color space, which closely matches human color sensation. However, keep in mind that the match is very good but not perfect. For example, Lab does not provide perceptual uniformity. The Munsell Color System most closely matches human color sensation. It provides perceptual uniformity for lightness, chroma, and hue. So far, there are no color correction tools for the Munsell color space, but we have implemented a perceptually uniform compensation algorithm in FireGrade.


What is Lch, and in which way is it better than Lab? Actually, Lch is essentially the same thing as Lab, only represented cylindrically. But why is it better? That’s because it is easier to work with colors if you split them into chroma (с) and hue (h) instead of using the ab coordinates. For example, it is much easier to grasp "Chroma = 60, Hue = 135" than “a = -42, b = 42” (at least, for humans). In this case, the combination of values corresponds to a “greenish” color. Hue shows the “greenishness” (color tone), and Chroma shows chromaticity (that is, how “colorful” the color is, what is its “color power,” the intensity of “greenishness”).


It is always easier to manipulate only one component rather than two, let alone three. Working in Lch, you can quickly and easily “think” in these metrics, so you can manipulate each color component separately.


Both in Lab and Lch, L stands for Lightness.



Lch color space looks like this:


Lch color space






Installing the plugin


Before installing FireGrade, please verify that your hardware and software meet or exceed the minimum system requirements.




Windows 10 x64 build 2004

4 GB free RAM

100 MB free disk space

1920x1080 screen resolution

Adobe Photoshop CC or higher




macOS 10.13 ~11.2 (Intel only)

4 GB free RAM

100 MB free disk space

1920x1080 screen resolution

Adobe Photoshop CC or higher





Before installation please uninstall old version (1.3.x or older) first!


How to uninstall: go to Windows Settings -> Apps -> Apps & features -> point to "FireGrade"-> click Uninstall.



Installing FireGrade on Windows. Run FireGrade.exe and follow the installation wizard:



FireGrade installation EULA dialog



FireGrade installation folder question



FireGrade ready to install dialog



FireGrade installation process dialog


FireGrade end of installation dialog








In first run FireGrade ask you for license or start trial:



FireGrade ask for license diallog


Click on "Enter license" button and paste your license key into this window:


FireGrade license window


Then click OK button,


If the license is valid and you did everything right, you can start using FireGrade.



Using the plugin


You can find the plugin in the Adobe Photoshop filters menu: Filter -> Nuclear Light -> FireGrade


FireGrade in Photoshop menu



As we said above, FireGrade works in the Lab color space. So your image must be in that color space, too. But what if you have a complex document with lots of mask layers and other stuff, it is in RGB or CMYK, and you do not want to switch to the Lab mode? Smart objects will come to help!


Convert the layer of interest to a smart object, open the object, convert it to Lab, use FireGrade, and save the changes. If you need to do “nondestructive” editing (that is, you may want to do corrections at any moment), convert the layer inside the smart object into another smart object, and apply FireGrade. Now you can open the smart object again to make changes.


Smart objects are a standard feature of Adobe Photoshop, and here we just showed you some tips and tricks.


Keep in mind that because of the limited and varied gamut of displaying devices in the RGB/CMYK color spaces, the final result may differ from what you expected. That is especially true if after correction, the resulting color lies outside the document’s profile. The result may also differ from what you see in the FireGrade preview when using the plugin if your monitor’s profile doesn’t match the document’s profile. FireGrade always uses Adobe Photoshop to convert previews to the monitor’s profile. Therefore, we strongly recommend working in Lab, and converting the image to the RGB/CMYK target profile only at the final stage. This way, you can verify that the result of conversion is good, and possibly do necessary corrections.


We also recommend working in the 16 bits per channel mode, which will prevent unwanted posterization effect in some cases. Even though FireGrade internally uses floating point numbers, the 16 bits per channel mode will let you get better results compared to 8 bits per channel. Particularly, if you use the 8 bits per channel mode, quality may be compromised when you finally convert the image to the RGB/CMYK target profile. All in all, 16 bits per channel is better.



FireGrade does not impose any limits on image size. It can handle very big images. The only limit is imposed by Adobe Photoshop itself. At the moment, it is 300,000 by 300,000 pixels. Of course, you will need a powerful computer to process such a huge image.


FireGrade fully supports multi-core CPUs and multiple CPUs.



Remain parts of user manual will be coming soon


But for now you can watch this short guide





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