Computer workshop 2

We are using the spot colour channel in photoshop to create a tint. We have to work in greyscale for it to work. You go to the channels tab above the layers panel and select new spot channel. We then select the colour that we would like to work with. We started off with the solidarity at 100%. This allows you to paint with tints of one colour in a greyscale channel. 

The reason we work like this is to be able to use the image as a positive for screen printing, we are actually working in tones of black but the method allows us to se how our selected colours will work once we take the image to print.

If you want to use the magic wand tool to select sections of the image your need to skip back and forth between channels, something I keep forgetting to do. once we have added all the tones that we want, we can un tick the original channel to see how the tones look in grey scale.

The above image is without using the magic wand tool. it is messy but I would like to experiment with this to see if i could create some nice effects. The image below is using to magic want tool. This makes being neat a lot easier and could be used with vectored images to make some really crisp half tone images.

We save the document as a psd then open a blank document in illustrator and drag the file into it. When sending the image to print we go to the output and an chose separations. in the document ink options panel we can change frequency of the dot channel by altering the LPI number. if we chose 60 we will get a very fine detailed number of dots, the lower we go from there the more obvious the dots will be. I need to experiment with this too see what effect the variation in halftone has on the aesthetic of my prints. I like the idea of trying to use very obvious, bold half tones. 

If we want to be able to see the effect of half tone on screen we can bitmap the image in photoshop. The image has to be greyscale and flattened into one layer. You can do this by going to image and mode, completing those precesses then image and mode again and bitmap. When using bit map we are given a number of choices the main one being the output which is the number of pixels per inch. In other words the lower the number the more the image will be broken up into a simpler layout of larger blocks.

  

 I tried 1200 and 100 pixels per inch.