The easiest way to see what happens is to make up a very simple PCB design, add the solder mask where you want it then check the resultant Gerber files using gerbv or the EasyEDA Gerber Viewer: [https://docs.easyeda.com/en/Export/Export-Gerber-Files/index.html#Gerber-View](https://docs.easyeda.com/en/Export/Export-Gerber-Files/index.html#Gerber-View)

Just to confirm: If you draw: * Track; * Rect; * Solid Region (set to Solid); on the Silkscreen layer, then you will remove solder mask - and irrespective of what may already be defined - in the areas defined by the added shapes. So, yes you can "...remove solder mask over an area that does not have copper, so that LED's shining through the bottom of the PCB may shine-through without being tinted by the color mask."

I had the same problem. I wanted to remove soldermask in an area the shape of a donut. I ended up drawing a circle, and then playing with the parameters until the correct area was covered. By adjusting the width and diameter, and closing the half circle by dragging the end points, I ended up with a donut shaped area that fit my requirements. Set it to 'soldermask layer' and done. It took me a loooong time to figure out.

@andyfierman so to produce a transparent rectangle, I would need to create an area without copper on the top and bottom layer, then draw a rectangle on the silk layer top and bottom (to remove the soldermask). And finally remove the silkscreen rectangle.

@suicidebattery, It's easier than that. To create a translucent area of a PCB substrate material covered by copper you need to: 1. Remove copper (on all layers) to expose the substrate. If necessary, you can use a **Solid Region** set to **No Solid** and copy it to all layers with copper on them;  2. Create a suitable **solid** shape in the top and bottom layer SolderMask layers;. If there's no copper obscuring the area then only the shapes in the top and bottom layer SolderMask layers are required; However I should point out that you are posting in a 3 year old topic during which time: * I have found that there's a typo in my post (it should say SolderMask instead of SilkScreen);  * The link to the item in FAQ is broken; * The FAQ has been changed and the image no longer matches the text so the last paragraph of the text in the FAQ does not make sense. **For the avoidance of doubt therefore, please see: ** [https://oshwlab.com/andyfierman/how-to-make-an-aperture-in-the-solder-mask](https://oshwlab.com/andyfierman/how-to-make-an-aperture-in-the-solder-mask)<br> <br>

@suicidebattery, This procedure is now included in **How to Design PCBs**, (2.2) in **Welcome to EasyEDA**, (2) in: [https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a](https://easyeda.com/forum/topic/How-to-ask-for-help-and-get-an-answer-71b17a40d15442349eaecbfae083e46a)