Giclee: Allpconline Company Blog
Tuesday, April 19, 2005
Gamut compression and giclee printing
I feel we need to address the issue of digitally created files and giclee printing. As I wrote in past posts, giclee printers do have a wide color gamut, far surpassing that of conventional cmyk printing methods (press). This said, we do get digital files with such extreme colors and see clients who expect the chromatic rendition to match what they see on the screen. There is absolutely no way that a pure blue (RGB 0,0,255) can possibly be printed. What a printer will do is see that the colors cannot be rendered as indicated by the file and consequently compress the gamut to suit the paper profile. Different paper/printer combinations have different capabilities. Given the same printer, a glossy or satin photo like paper has a wider gamut than canvas. When choosing canvas, different types have different gamuts as well. Blues tend to be the hardest to reproduce and this is mostly due to the nature of the inks, which fall short when trying to reproduce bright blues. What can be done is to reduce saturation and sometimes change the hue to bring colors within printer/paper gamuts. If this is not done and gamut compression is left to the printer software, severe color shifts will happen.
Saturday, April 09, 2005
Analyzing your digital files for giclee
Let's look one more time at file preparation. As you know we do not provide a money back guarantee with client supplied digital files. The reason? We receive anywhere from perfect, fantastic tifs to very poor ones. What distinguishes the two is a matter of mainly 3 factors:
1)Resolution - This is simple, we need a minimun 200 ppi for the giclee size desired.
2)Information - Here it gets a little tricky. The best tool to see if your image has a complete tonal range is to run a histogram (in Photoshop) to check if there is any information missing in the highlights and shadows. The hystogram can also tell you if the image is too flat by representing empty space at the right and left of it. This is easy to correct by running levels and putting the cursors next to where the information starts.
3)Color accuracy - is the color true to what you want represented in the giclee? Is the blue you see on your screen reading 0 0 160 or 0 30 160? In the case of the latter, the blue may look so in an uncalibrated monitor but it will print with a green component.
Finally, very important, do you have any color crossover? Although it is fairly rare these days, we still encounter it!
1)Resolution - This is simple, we need a minimun 200 ppi for the giclee size desired.
2)Information - Here it gets a little tricky. The best tool to see if your image has a complete tonal range is to run a histogram (in Photoshop) to check if there is any information missing in the highlights and shadows. The hystogram can also tell you if the image is too flat by representing empty space at the right and left of it. This is easy to correct by running levels and putting the cursors next to where the information starts.
3)Color accuracy - is the color true to what you want represented in the giclee? Is the blue you see on your screen reading 0 0 160 or 0 30 160? In the case of the latter, the blue may look so in an uncalibrated monitor but it will print with a green component.
Finally, very important, do you have any color crossover? Although it is fairly rare these days, we still encounter it!
