My prints from scans (epson C80) have a case of the jaggies and I'm at a loss as to how to get ride of them. Even if I scale the file to 360 dpi sent to the printer, I still see jaggies in diagonal lines. I've tried scaling to 240 and then ressing up to 480 with no luck. My scanner now is an acer 1240ut flatbed, not the best, but not bad as far as flatbeds go. All scans are at the optical res limit of 1200. Maybe that's the problem, the scanner is giving much less resolution than 1200. I don't know, any thoughts?

-- Mark (acerview76eus@yahoo.com), April 21, 2002

Answers

It sounds like you are attempting to use a relatively low-resolution scan to print an image larger than its original dimensions will support, Mark. For printing purposes, it is usually best to scan at the highest resolution possible, and retain that admitedly very large file in an uncompressed format, such as Photoshop PSD or TIFF. Taking a version of the scan that has been resized for Web presentation, and scaling up or up-res'ing it to a larger file doesn't work well.

Assuming that you are scanning your negs at 1200 DPI/PPI (the stated limit for your scanner), and then trying to print them, you'd end up with a scan containing about 1123 x 1684 pixels from a 24mm x 36mm negative. Printing that image at 300 DPI would give you a print of not quite 4" x 6". You may be able to up-res the original scan a bit, by doing it in steps of 20% or less (going from 1123 pixels to 1347, for example), but quality is lost in doing so. The printer's interpolation capabilities also play into the equation, but the fundamental choices are to get a scanner with higher resolution, or settle for smaller prints.

By comparison, a 4000 DPI film scanner would yeild about 3744 x 5616 pixels - much better for larger prints.

-- Ralph Barker (rbarker@pacbell.net), April 21, 2002.

Ralph,

That's what I do, scan at 1200 ppi, save as a tiff in Photoshop Elements, set the image size to 360 or 300 or 240 ppi (No resample) and then print. Even using 360, I see slight jaggies on diagonal lines. I have no problem with small prints, if I want something larger I send it out. I just wonder why I'm still seeing the jaggies?

-- Mark (acerview76eus@yahoo.com), April 21, 2002.

I just wonder why I'm still seeing the jaggies?

I'm not familiar with the specifics of your printer, but here are a couple of things to look into. (I'm basing my suggestions on what I've seen printing digitized files on my Epson 1200 from a full version of Photoshop, so your mileage may vary, as they say. I can, however, print good 8x10s and reasonable 11x14s from Nikon D-1 files, which are only 1320x2000 pixels in size.)

Most inkjets will take the image file and interpolate that data into the native print resolution of the printer (e.g. 1440 or 2880 DPI on most Epson photo printers). That process introduces, I believe, an anti-aliasing technique to soften the edges of the additional pixels being generated in software, so the resulting print still looks fairly sharp at normal viewing distances. If you're seeing the jaggies at normal viewing distances, you may have a mismatch between your drivers and the printer. (Remember, however, that pixels are rectangular in shape, so at magnification, there is no such thing as a straight diagonal line.)

It could be that the printer driver you have for your printer doesn't handle TIFFs well (look for an updated driver, or try saving in .PSD format and see if that makes a difference). Or, not finding a driver for that printer, it might be using a generic driver that doesn't trigger the printer's interpolation routines (assuming the printer will actually do that). I'd first check the specs on the printer, and then try to contact Epson tech support or a group that concentrates on digital printing.

-- Ralph Barker (rbarker@pacbell.net), April 21, 2002.

How big a print are you trying to print? With 1200 dpi and a 35mm negative, you can't go bigger than 4x6 unless you use Genuine Fractals or something similar.

-- Jeff Spirer (jeff@spirer.com), April 21, 2002.

Jeff,

I'm printing to a final size that gives either 360, 300, or 240 dpi in the print usually about 3x5, 4x6, or 5x7, but as I said, I only scale with the dpi setting in PS and live with whatever print size it gives me. I going to play around a little more today and try Ralphs suggestions. Let me know if you have any ideas.

thanks

-- Mark (acerview76eus@yahoo.com), April 24, 2002.

Mark - Are you using edge smoothing in the C80 driver? That might help. Also, the C80 was not designed as photo printer and its output is not as good as some of the Epson photo printers.

-- Jeff Spirer (jeff@spirer.com), April 24, 2002.