9 Replies Latest reply on May 12, 2008 12:23 AM by (koki)

    change dot gain to 5%

      hello!

      i want change dot gain to 5% in pS.

      now i have 10% in gray menu.

      any idea?
        • 1. Re: change dot gain to 5%
          Lou Dina Level 3
          koki,

          I am assuming you want a grayscale image? If so, bring up an image in PS. Then from the Menu bar, Edit>Convert to Profile, then select "Custom Dot Gain" in the "Destination Space" box. When the "Custom Dot Gain" window shows up, enter 55 in the 50% box. This is a 5% dot gain and will give you a much flatter curve than the typical 20% dot gain (which shows 70 in the 50% box).

          For what it's worth, 5% is an extremely low dot gain for most printing conditions.

          If you want a color image, you can do similar things by selecting Custom CMYK instead of Custom Dot Gain. You can even create custom RGB profiles with different gamma levels.

          Lou
          • 2. Re: change dot gain to 5%
            thank's, LOU

            but away, how you now abut 55 in 50%? it's any sistm to
            now this?
            • 3. Re: change dot gain to 5%
              Gray > Open Menue > Click on upper Custom DotGain
              Modify default tone reproduction curve by new value y=55%
              at old value x=50% (banana upwards, IF black is to the
              right on the x-axis and on top for the y-axis).

              Best regards --Gernot Hoffmann
              • 4. Re: change dot gain to 5%
                Level 1
                thank you very much.

                do you now any professional program how bilding profille
                except pS?
                • 5. Re: change dot gain to 5%
                  Larry Tseng Level 1
                  Hi Kokii,

                  There are quite a number of commercial programs that you can choose from to build color profiles, but none for grayscales unfortunately.

                  Larry
                  • 6. Re: change dot gain to 5%
                    Level 1
                    do you have any link for this programs for color?

                    thank
                    • 7. Re: change dot gain to 5%
                      Larry Tseng Level 1
                      Kokii,

                      The X-Rite website might be a good place to start.

                      http://www.xrite.com/top_Products.aspx

                      I would also google "color management" for other manufacturers, as well as look at some stores. Here's one with brand names that you can later check out on the web.

                      http://www.colormanagement.com/store

                      Larry
                      • 8. Re: change dot gain to 5%
                        Lou Dina Level 3
                        kokii,

                        Dot gain (also called TVI, or tone value increase) usually refers to how much a 50% dot increases in size when ink hits paper. They use the 50% dot, since it usually exhibits the most increase in size. A 90% or 100% dot already is approaching solid coverage, so the dot gain is lower. And a 5% or 10% dot represents very little ink hitting the paper, so it also has a minimal dot gain.

                        If the dot gain for a given press and paper is 20%, a 50% dot will measure 70% (a 20 point increase). With a 15% dot gain, a 50% dot will end up measuring 65% (a 15 point increase). So, if a printer knows he will get have a 20% dot gain on a certain type of paper using a certain type of printing device, you should get a good print if you provide separations that have the same dot gain. When you provide separations that take dot gain into account, your separations become lighter, since you anticipate the fact that ink will expand and darken the image when it reacts with the paper. As implied above, dot gain affects the midtones more than it does the highlights or shadows. The higher the dot gain in your separations, the lighter it is, since you expect it to darken quite a bit. A 5% dot gain will give you a separation that is very close in density to the final image, since you anticipate almost no spreading of ink.

                        Using an incorrect dot gain can have some unpleasant results. If you separate a file using 5% dot gain, and the dot gain of the actual printing condition is closer to 20%, your printed image will come out dark.

                        Dot gain, or TVI, can be accounted for by using custom ICC profiles, or it can be done using the method I suggested earlier. ICC profiles are generated by comparing a standard test target to a printed sample, and make adjustments accordingly when a file is converted to that profile. So, it accounts for dot gain automatically. The profile is only valid for the conditions, equipment, paper and ink used to create it.

                        Many commercial printers don't know what their dot gain actually is. If you ask them, they may give you incorrect data, or they may give you a low figure, since that usually suggests higher quality. It is usually fairly common for a sheetfed press to have a dot gain in the 15-20% range on quality coated stock. Web presses usually have a higher dot gain since they run faster and tend to use less expensive paper. Newprint has dot gains that are typically 30-35%, due to the cheap paper they use. These numbers vary considerably from press to press, and paper to paper. Usually, the better the press and the better the paper, the lower the dot gain, but other factors also affect dot gain, including line screen, temperature and humidity, press speed, ink tack, press maintenance, etc.

                        Just remember than dot gain, or TVI, refers to how much a 50% dot expands when ink hits paper, and you will get the idea.

                        Lou
                        • 9. Re: change dot gain to 5%
                          Level 1
                          thank you very much, lou!