CMYK separation screen printing.

A quick overview of the color separation process with screen printing (aka: Silk screen, & serigraph) For a more in-depth study check out the Screen Printing Glossary (here) by the American Screen Printing Association. 

The body of work that I have been developing is somewhere between the realm of traditional "analog" art and digital collage. This process fits my goals well. I will write more about the content of the work on a later date, but for now I want to show the process.

The first step is to get an image that you want to print. For me that means making a digital collage in Photoshop. 

Below is a crop of one of the collages, showing 3 of the 5 eggs that will make the composition. I am trusting you, internet, not to take this image and claim it as your own. Don't do that. That's rude. Besides, it's a rough one, not very refined, you can do better.

 I will skip the layers and masks explanation because that is readily available on youtube by hundreds of users. A blog really isn't as good as a video explanation anyway. 

I will skip the layers and masks explanation because that is readily available on youtube by hundreds of users. A blog really isn't as good as a video explanation anyway. 


Next you have to separate the layers of your image into the CMYK layers. C for Cyan, M for Magenta, Y for Yellow, and K for key (or black). This is a standard print setting. For images that are digital, and going to stay that way, many artists make the work in RGB mode (Red, Green, Blue) which is most appropriate for how colors are combined in light to make a full spectrum. Many dancers or theater folks understand color theory when it comes to light and how it's very different than color theory in physical pigment. 

 This image, and a full description of color light/pigment from  here

This image, and a full description of color light/pigment from here


Once the colors are separated into their own layer files they will look black. This is to give the viewer an idea of where the color pigments sits on the surface of the canvas (the substrate... can be paper, background, etc). For screen printing you need to then convert these files into a bitmap. That will simplify the image in to a series of dots or ellipses. During that conversion you have to change the direction of the dots so a pattern wont appear as a result of the layering and threads on the screen. You also have to consider the thread count of the screen you will be using, and the level of detail in your image. That will determine the dpi (dots per inch) of the bitmap. For mine, I have a 305 thread count screen, and a lot of fine detail and color mixing to do so I put the dpi at about 175 (a little more than half the thread count is a good general guide line). I am using a toner printer, not a large format photo printer. This is about as good as I can get it, but using a large format printer would give one better results. 

 When converting your image to a bitmap, after deturmining the DPI, you need to set the angle for each layer. This image, and more info from  here . As you can see, getting the angle right will prevent patterning on the surface. I generally use the one on the top-right, which results in the most even distribution of color with the least patterning.

When converting your image to a bitmap, after deturmining the DPI, you need to set the angle for each layer. This image, and more info from here. As you can see, getting the angle right will prevent patterning on the surface. I generally use the one on the top-right, which results in the most even distribution of color with the least patterning.


Next the layers are printed out on transparent film, and burned into the coated silk screen. 

 All layers will print out black, regardless of what color they are. 

All layers will print out black, regardless of what color they are. 

It would benefit you to label your layers, especially of they don't look very different from one layer to another. The black toner will block the light from exposing some areas of the coated screen. Once the emulsion is done hardening from exposure to light, you rinse out the screen which will reveal the parts that were protected by the toner. Those areas will wash clean. 

 I have a photo-exposure bulb on the screen here. As you can see, I placed the transparencies over the freshly dried, photo sensitive emulsion. The bulb cooks the parts that light hits, and the rest remains soft. Water will rinse those parts away from the screen. (You can also see a ghost of a previous print on the screen. That happens sometimes with dark inks. It wont affect future prints)

I have a photo-exposure bulb on the screen here. As you can see, I placed the transparencies over the freshly dried, photo sensitive emulsion. The bulb cooks the parts that light hits, and the rest remains soft. Water will rinse those parts away from the screen. (You can also see a ghost of a previous print on the screen. That happens sometimes with dark inks. It wont affect future prints)

 Here are my exposed screens, showing the cyan and magenta layers burned into the emulsion. Look close to see the differences between those layers, the yellow areas are open and will allow the screen print ink to pass through. 

Here are my exposed screens, showing the cyan and magenta layers burned into the emulsion. Look close to see the differences between those layers, the yellow areas are open and will allow the screen print ink to pass through. 


Next, I generally try to print the image by starting with the lightest color, and building to darkest. Below are images of two prints in progress that already have the yellow, and cyan layers on them. 

 Seen here are some images that already have the yellow, and cyan layers down. 

Seen here are some images that already have the yellow, and cyan layers down. 


 I am getting ready to lay down the magenta layer here, so to (try to) get the registration right I run the ink through once on a blank piece of transparent film.

I am getting ready to lay down the magenta layer here, so to (try to) get the registration right I run the ink through once on a blank piece of transparent film.

 When I slide the image under the film, I can line it up with the image to get the paper under the correct part of the screen. 

When I slide the image under the film, I can line it up with the image to get the paper under the correct part of the screen. 

 Here is what happens when registration goes sideways! This print is hard.

Here is what happens when registration goes sideways! This print is hard.

 Everything about my studio is DIY, but this drying situation has to be the most! It's literally paper, binder clips, and yarn tacked to the wall. It works in a pinch, but the paper will warp during drying and need to be flattened. 

Everything about my studio is DIY, but this drying situation has to be the most! It's literally paper, binder clips, and yarn tacked to the wall. It works in a pinch, but the paper will warp during drying and need to be flattened. 

 Here's the finished print for the single egg and skull composition

Here's the finished print for the single egg and skull composition

 Here's the finished print for the growing eggs composition

Here's the finished print for the growing eggs composition


And there you go. I hope you found this process post interesting. Please feel free to reach out if you have any thoughts or questions! Thanks for reading.