Hello
I'm occasionally using CD X4 just for fun (so i'm not that experienced). My friend who has a digital printer, once printed one of my designs but there were stripes (like you have when there's little ink in a printer) only in gradient filled areas When i fill a shape with gradient colors, i also see these stripes on my screen (when i look very close) in CD and also in pdf when i export the file. What can i do? Thank you. david from belgium
One option is to Print the Document as a Bitmap.
I believe it's called Rasterize in CorelDRAW X4.
Another option is to increase the Fountain Steps. With the shape selected, press F11 to bring up the fill dialog. Change the input field for steps to a higher value.
FYI, increasing the fill steps doesn't necessarily enhance the result. In fact it may even make it worse.
You see when the padlock is closed (steps box is greyed out) Draw creates the fill by specifying only the end colors (and mid colors, if any) and the printer/RIP recreates the fill with as many steps as it possibly can.By setting a specific number of steps, you limit the fill to that number, but in reality it may not be 999 even if that's what you've set it to be. In fact it may be very few steps, depending on which colors are in the fill.I've seen this myself when I printed a sign with a large dark brown radial fill. The black color in the fill only permitted 20 steps (K70 to K90) even though I had it set to 999. By locking it I got a much better result.
I've looked at the code which Corel (versions up to at least X4) sends to postscript printers for blends, fountain fills, etc.
It is stupid.
For example, if you have a blend from 10% to 20% and ask for 9 intermediatesteps, then you get exactly what you would expect -- 10%, 11%, 12% ... etc to ... 19% 20%. However, if you ask for 19 steps ... then you get 21 objects, but 10 of them are the same colour as 10 of the other 11.
I don't think Corel intends this to happen, but tints are output as a value from 0 to 1 with only 2 decimal places. Consequently every step is resolved to the nearest whole-percent tint ... which is why no matter what you do, you cannot get more than 9 visible intermediate steps between a 10% to 20% fill.
And then ... you'll notice that I chose strange numbers of 9 and 19 for my examples. Most people would choose round numbers -- but if you have 20 intermediate steps, it makes things even worse. Instead of having exactly two steps for each tint value, you have one in the middle which has three steps with identical tints. As far as the eye can see, this amounts to just 11 steps -- but the middle step is 50% wider than all the other steps.
It is this wider step which stands out like a sore thumb in the finished graduation and which can make graduations worse if you increase the number of steps without ensuring it is an exact multiple of the difference between the top and bottom tint.
And then it gets worse ... if you have a CMYK blend rather than just grey. Imagine you have a blend which spans 7% cyan and 11% yellow. There is now no optimum number of steps at all, because the cyan and yellow components will usually increment on different steps, again creating bands which stand out as a tint of a different colour (too much cyan or too much yellow) from that which the eye expects to see in that place.
Corel might have fixed this in X5, but if not then it would be a very simple fix -- use 3 or 4 decimal places for tint values instead of 2, or represent the tint by the result of a postscript calculation.
harryLondon said:I've looked at the code which Corel (versions up to at least X4) sends to postscript printers for blends, fountain fills, etc.