TshirtGuru

What is the difference between index separation versus simulated process?

To my understanding, INDEX are bitmap shapes, and SIMULATED is done with halftone dots.

Is that the biggest difference? I just did my first INDEX printing for a customer today and it came out awesome. I'm very excited.

Now, I'm just guessing that I know how to INDEX, all I have to do is INDEX separate the image and then at the last step, BITMAP the image and halftone dot it instead of just BITMAP dither.

 

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marcelolopez

Congratulations...my process inks just arrived !! I am very eager to give it a try.

I have just stolen this from screenprinters.net :

Simulated Process Color
This is also known as "fake"; process color. Simulated Process color images have a photorealistic look but are not printed with the process colors of CMYK . They look like process, smell like process, feel like process but aren't process. The color separations for simulated process color are made up of halftone images of spot colors like red, yellow, blue, etc. They are often called "tonal"; or "channel"; separations . Simulated process separations can be printed on light and dark shirts and are generally done in Adobe Photoshop.
Because the inks for simulated process color are generally all-purpose, semi-transparent plastisol they give you a bright print even when printed on an underbase of white ink. When done correctly, simulated process prints can be very photorealistic with smooth gradations and bright colors.
Index Color
This is probably the most confusing of the separation methods. For simulated process, real CMYK process and spot colors with gradations, any shading is done with different size halftone dots that have a definite pattern and angle to them . Index separations are done in Adobe Photoshop and use a random square dots that are all the same size. These random dot patterns are also often called diffusion dither or stochastic

Index color separations are done in Adobe Photoshop by creating a color table of the most prominent colors in your image (and the most colors you are capable of printing) and then letting Photoshop convert the image to just those colors using random square dots. Photoshop will make (or try to make) the image look as close as the original as possible with just the limited number of colors you selected.
Index prints can be very bright on light and dark shirts and the separations are easy to do. The downside to index prints is that for the image to be photorealistic you need at least six colors and in some cases eight to ten colors. Index prints can sometimes have a grainy and textured look to them. When printed with a lot of colors index prints can also be very striking ! Index separations work great for spot color images too. They are also easy to print because you are placing a dot next to a dot rather than printing halftone dots on top of halftone dots. Just don't use indexing because someone told you that halftones are hard. Most of the award winning prints you see are still real process color and simulated process color.

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TshirtGuru

Do you know how to manually separate simulated process in photoshop?

 

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douglasgrigar

Quote: Originally Posted by marcelolopez Congratulations...my process inks just arrived !! I am very eager to give it a try. I have just stolen this from screenprinters.net : Simulated Process Color This is also known as "fake"; process color. Simulated Process color images have a photorealistic look but are not printed with the process colors of CMYK . They look like process, smell like process, feel like process but aren't process. The color separations for simulated process color are made up of halftone images of spot colors like red, yellow, blue, etc. They are often called "tonal"; or "channel"; separations . Simulated process separations can be printed on light and dark shirts and are generally done in Adobe Photoshop. Because the inks for simulated process color are generally all-purpose, semi-transparent plastisol they give you a bright print even when printed on an underbase of white ink. When done correctly, simulated process prints can be very photorealistic with smooth gradations and bright colors. Index Color This is probably the most confusing of the separation methods. For simulated process, real CMYK process and spot colors with gradations, any shading is done with different size halftone dots that have a definite pattern and angle to them . Index separations are done in Adobe Photoshop and use a random square dots that are all the same size. These random dot patterns are also often called diffusion dither or stochastic Index color separations are done in Adobe Photoshop by creating a color table of the most prominent colors in your image (and the most colors you are capable of printing) and then letting Photoshop convert the image to just those colors using random square dots. Photoshop will make (or try to make) the image look as close as the original as possible with just the limited number of colors you selected. Index prints can be very bright on light and dark shirts and the separations are easy to do. The downside to index prints is that for the image to be photorealistic you need at least six colors and in some cases eight to ten colors. Index prints can sometimes have a grainy and textured look to them. When printed with a lot of colors index prints can also be very striking ! Index separations work great for spot color images too. They are also easy to print because you are placing a dot next to a dot rather than printing halftone dots on top of halftone dots. Just don't use indexing because someone told you that halftones are hard. Most of the award winning prints you see are still real process color and simulated process color.

Nicely done marcelolopez...

I would have to add that Simulated/Spot Process is best on dark shirts with an opaque ink rather than a "GP" ink. Index is actually a form or sub-category of Simulated/Spot Process, artists like myself started working on Simulated/Spot Process back before computers by hand with a "rapidiagraph" pen or traditional artist ink pins and lots of contact film exposures.

Index usually requires more colors and because of the "first order" stochastic dots can have a "soft focus" look.

If you want to see an article I wrote about stochastic dots, it is available on my blog.

I usually prefer Simulated/Spot Process because as an artist it often gives more control over the final "look and feel" of the print.

 

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