Suppose I'm designing something for printing purposes. Then I need to stick with CMYK model. When ever I'm choosing color while designing, I'm setting color based on what my monitor shows me as CMYK. But Monitors don't work on CMYK. So, what my monitor showing is a conversion of that CMYK in RGB. After reading little bit, now I understood that CMYK and RGB are not exactly convertible and there are color always some differences. So, what I'm seeing is not the color I actually set.
Legal-size envelope. Lay the legal paper, printed side up, on a flat surface. Fold the bottom edge of the paper upward, creasing it across, 5 inches from the bottom. Use a ruler to make sure that the crease is exactly 5 inches from the bottom edge. This will leave the top 4 inches of the paper exposed.
This will leave 2 1/2 inches on the bottom since the paper is 8 1/2 inches wide. Then, take that 2 1/2 inch section on the bottom and carefully fold it up over the top of the part you folded down in the first step. Make a good crease in the paper, then fold that back and also fold back the diagonal section from step one. Now, re-fold the 2 1/2 inch section from the bottom and use a pencil and draw a line carefully across the page where the 2 1/2 part ends. The paper will be exactly 6 inches above the line and 5 inches below.