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author | Roger Leigh <rleigh@debian.org> | 2008-10-26 16:11:41 +0000 |
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committer | Roger Leigh <rleigh@debian.org> | 2008-10-26 16:11:41 +0000 |
commit | dfae5860833782af557deb35e286d7e186fe3cf5 (patch) | |
tree | e3b4282ae08e120f78cd0c097f7cb3b570e94da2 /doc/manual-html/gimpprint_43.html | |
parent | 3b59bb0a607ec27ea60f07d1cd5d1bbb4483c832 (diff) |
Imported Upstream version 4.3.99+cvs20050702
Diffstat (limited to 'doc/manual-html/gimpprint_43.html')
-rw-r--r-- | doc/manual-html/gimpprint_43.html | 189 |
1 files changed, 0 insertions, 189 deletions
diff --git a/doc/manual-html/gimpprint_43.html b/doc/manual-html/gimpprint_43.html deleted file mode 100644 index 381ac9c..0000000 --- a/doc/manual-html/gimpprint_43.html +++ /dev/null @@ -1,189 +0,0 @@ -<HTML> -<HEAD> -<!-- This HTML file has been created by texi2html 1.51 - from .././gimpprint.texi on 11 June 2004 --> - -<TITLE>GIMP-Print - Tuning Epson printers</TITLE> -</HEAD> -<BODY> -Go to the <A HREF="gimpprint_1.html">first</A>, <A HREF="gimpprint_42.html">previous</A>, <A HREF="gimpprint_44.html">next</A>, <A HREF="gimpprint_47.html">last</A> section, <A HREF="gimpprint_toc.html">table of contents</A>. -<P><HR><P> - - -<H2><A NAME="SEC58" HREF="gimpprint_toc.html#TOC58">D.4 Tuning the printer</A></H2> -<P> -<A NAME="IDX265"></A> -<A NAME="IDX266"></A> - -</P> -<P> -Now, how do you use all this to tune a printer? There are a number of -ways to do it; this one is my personal favorite. - -</P> -<P> -There's a file named <TT>`cyan-sweep.tif'</TT>. This consists of a thin bar -of cyan sweeping from white to almost pure cyan, and from pure cyan to -black. The first thing to do is to pick the appropriate -<CODE>simple_dither_range_t</CODE> (or create a whole new -<CODE>escp2_variable_inklist_t</CODE>) and comment out all but the darkest ink -(this means you'll be using the largest dots of dark ink). At 8.5" -width (the width of a letter-size piece of paper), the bar will be 1/8" -high. Printing it on wider or narrower paper will change the height -accordingly. Print it width-wise across a piece of photo quality paper -in line art mode using ordered or adaptive hybrid dither. Do not use -photographic mode; the colors in photographic mode vary non-linearly -depending upon the presence of the three color components, while in line -art mode the colors are much purer. Make sure that all the color -adjustments are set to defaults (1.0). Use the highest quality version -of the print mode you're testing to reduce banding and other artifacts. -This is much easier to do with the Gimp than with Ghostscript. - -</P> -<P> -At this stage, you want to look for four things: - -</P> - -<OL> -<LI> - -The black near the center of the line is solid, but not more so than -that. - -<LI> - -The cyan immediately to the left of the black is <EM>almost</EM> solid. - -<LI> - -The dark cyan at the far right of the page is solid, but not more so. -You can try tuning the density so that it isn't quite solid, then -nudging up the density until it is. - -<LI> - -Both sweeps sweep smoothly from light to dark. In particular, the dark -half of the bar shouldn't visibly change color; it should go smoothly -from cyan to black. -</OL> - -<P> -Repeat this stage until you have everything just right. Use the -positioning entry boxes in the dialog to position each bar exactly -1/8" further down the page. Adjacent bars will be touching. - -</P> -<P> -The next step is to uncomment out the second darkest dot size. If -you're using variable dots, use the second largest dot size of the -dark ink rather than the largest dot size of the light ink. This will -give you two inks. - -</P> -<P> -When you recompile the plugin, you simply need to copy the new -executable into the correct place. You do not need to exit and -restart the Gimp. - -</P> -<P> -Print another bar adjacent to the first one. Your goal is to match -the bar using a single dot size as closely as possible. You'll find -that the dark region of the bar shouldn't change to any great degree, -but the light half probably will. If the lighter part of the light -half is too dark, you need to increase the value of the smaller dot; -if it's too light, you need to decrease the value. The reasoning is -that if the value is too low, the ink isn't being given enough credit -for its contribution to the darkness of the ink, and vice versa. -Repeat until you have a good match. Make sure you let the ink dry -fully, which will take a few minutes. Wet ink will look too dark. -Don't look at the paper too closely; hold it at a distance. The extra -graininess of the largest dot size will probably make it look lighter -than it should; if you hold it far enough away so that you can't see -the dots, you'll get a more accurate picture of what's going on. - -</P> -<P> -After you have what looks like a good match, print another bar using -only the largest dot size (or dark ink, for single dot size 6-color -printers). You want to ensure that the bars touching each other look -identical, or as close as possible to it; your eye won't give you a -good reading if the bars are separated from each other. You'll -probably have to repeat the procedure. - -</P> -<P> -The next step is to comment out all but the largest and third-largest -dot size, and repeat the procedure. When they match, use all three -dot sizes of dark ink. Again, the goal is to match the single dot -size. - -</P> -<P> -You'll probably find the match is imperfect. Now you have to figure -out what region isn't right, which takes some experimentation. Even -small adjustments can make a noticeable difference in what you see. -At this stage, it's very important to hold the page far enough from -your eye; when you use all three dot sizes, the texture will be much -more even, which sometimes makes it look darker and sometimes lighter. - -</P> -<P> -After this is calibrated, it's time to calibrate the light ink against -the dark ink. To do this, comment out all but the large dot version -of the two inks, and repeat the procedure. This is trickier, because -the hues of the inks might not be quite identical. Look at the dark -half of the bar as well as the light half to see that the hue really -doesn't change as you sweep from cyan to black. Sometimes it's easier -to judge that way. You may find that it looks blotchy, in which case -you should switch from ordered dither to adaptive hybrid. - -</P> -<P> -After you have the light and dark inks calibrated against each other, -it's time to add everything back in. Usually you don't want to use -the largest dot size of light ink. These dots will be much larger -than the small dots of dark ink, but they'll still be lighter. This -will cause problems when printing mixed colors, since you'll be -depositing more ink on lighter regions of the page, and you'll -probably get strange color casts that you can't get rid of in neutral -tones. I normally use only the smallest one or two dot sizes of light -ink. - -</P> -<P> -After you've tweaked everything, print the color bar with saturation -set to zero. This will print neutral tones using color inks. Your -goal here is to look for neutral tonality. If you're using a 6-color -printer and get a yellow cast, it means that the values for your light -inks are too high (remember, that means they're getting too much -credit, so you're not depositing enough cyan and magenta ink, and the -yellow dominates). If you get a bluish or bluish-purple cast, your -light inks are too low (you're not giving them enough credit, so too -much cyan and magenta is deposited, which overwhelms the yellow). -Make sure you do this on very white, very high grade inkjet paper -that's designed for 1440x720 dpi or higher; otherwise the ink will -spread on contact and you'll get values that aren't really true for -high grade paper. You can, of course, calibrate for low grade paper -if that's what you're going to use, but that shouldn't be put into the -distribution. - -</P> -<P> -You can also fully desaturate this bar inside the Gimp and print it as -monochrome (don't print the cyan as monochrome; the driver does funny -things with luminance), for comparison. You'll find it very hard to -get rid of all color casts. - -</P> -<P> -There are other ways of tuning printers, but this one works pretty -well for me. - -</P> - -<P><HR><P> -Go to the <A HREF="gimpprint_1.html">first</A>, <A HREF="gimpprint_42.html">previous</A>, <A HREF="gimpprint_44.html">next</A>, <A HREF="gimpprint_47.html">last</A> section, <A HREF="gimpprint_toc.html">table of contents</A>. -</BODY> -</HTML> |