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Lithography Report Lauryn Harriford | GC1040 | Summer 2017 Process Multiple thumbnails were sketched to get an idea for the layout of the postcard. Once the most desirable thumbnail was chosen, it was recreated using Adobe Photoshop. The Photoshop file was then converted to , saved, then made into a duotone file. The two spot used in the duotone was a tealish turquoise , and . A layout was created using Adobe Illustrator. The layout consisted of a 3’’x 5’’ rectangle with 0.125’’ bleeds for the duotone image and a smaller rectangle beside it for the grayscale image (for reference purposes). Plates were then made with 3 sets of images on them, then printed using the lithographic press.

What’s the difference? Duotone, grayscale, and process color images are three completely different things. Duotone images consist of two colors (hence the stem “duo”), they can be any two colors and can have tints. When two contrasting colors are chosen, the highlights and shadows in a duotone image are much easier to see. A grayscale image can consist of up to 256 different tones of gray between the blackest black and whitest . Grayscale images also define the highlights and shadows within an image. It is an image in which the value of each pixel is a single sample, thus is only carries intensity information, it can range drastically in intensity. The difference between a duotone image and a grayscale image is that duotones only consist of two colors while grayscale images can have up to 256 different and white. Process color has an even larger tonal range. They consist of the subtractive primary colors, which are , magenta, and cyan, along with black. These colors are mixed visually as opposed to physically. Varying combinations of tiny, closely spaced dots of cyan, magenta, and yellow ink absorb and reflect the different wavelengths of to produce different colors. The pictures below give a very good visual representation showing the differences between the three types of colors.

PAGE 1 Grayscale Duotone

Process Color

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Raster Image Requirements The original image must be an image containing pixels. It should be a minimum of 200 ppi and 3.125’’x5.125’’. The image I chose contained highlights, shadows, and had a dynamic tonal range.

Overprint Vector Art Vs. Process Color Vector Art Overprinting occurs due to opaque overlapping colors, when the top color overpowers the color underneath. This can be prevented by making the top layer of ink slightly transparent in relation to the inks underneath. The percentage of transparency will depend on the type of ink, the printing method, and the substrate. Overprint is a very common issue in the printing industry. Process color vector art is any type of art that does not contain pixels, and can consist of a very wide range of color possibilities. The colors cyan, magenta, yellow, and black are all combined in different percentages to make various colors. So the main difference between overprint vector art and process color vector art is that overprint may appear slightly darker or more dull compared to process color vector art.

Conclusion The ink density appeared to decrease in darkness from left to right on the sheet. It also appeared to be darker than the ink chosen in the computer program used to make the original image. This could be compensated by lowering the tint of the , or choosing a lighter color.

Lithography is a very good method to use for printing postcards. It was fast, effective, and efficient. The hardest part about the process was rigging the machine so that excess ink would not occur in undesirable areas of the sheet. I would recommend choosing an image with a dynamic tonal range. The image should have various highlights, midtones, and shadows. Images with these qualities look the best when converted to a duotone. I would also suggest choosing black and a bright/pigmented color for the two duotone color choices in order to get the best results.

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Appendix

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