Linescreen Equivalents

Peter Detheridge wrote:

Can any one please offer me a rule of thumb for calulating scanning resolution for inkjet printing.

I have heard of a rule of thumb that says that you can divide the maximum of the printers resolution with the number of colors in the printer. If it’s a 4 color 1440 dpi inkjet printer, then you need an image at around 360 ppi. If the 1440 dpi inkjet has 6 colors then you only need 240 ppi.

My inkjet printer has 7 colors and the maximum resolution is 2880 dpi. With the above rule of thumb I should use images at around 410 ppi when printing in the printers highest resolution. That’s more than enough in my opinion, but rules of thumbs are, well, only rules of thumbs. 🙂

—
Regards
Madsen.

On Tue, 12 Aug 2003 04:57:07 GMT, "Peter Detheridge" wrote:

Can any one please offer me a rule of thumb for calulating scanning resolution for inkjet printing.

Thanks.

Peter

Since inkjets do not produce halftones, the "line screen" is irrelevant.

Just to start, try printing a black and white photo on the inkjet. Create the photo at 8 x 10 and 300 dpi, and then down sample a *copy* at 150 dpi. Print both and compare them through a loupe.

And for even better results you can use all inks in the printer (i.e., don’t print with just black).

In my experience, for the majority of the images, the printed 150 dpi image is comparable to the 300 dpi image (on an inkjet, if you were scanning for offset press reproduction then 300 is the way to go).

If you used a higher resolution for the above test image (above 300), and then view a sample I will bet that you’d be hard pressed to see any improvement in the inkjet image.

The same goes for color images.

So the answer is, you need not scan at higher than 300 dpi (unless you think that you’ll enlarge the image so that the final image sent to the printer will be 300 dpi).

The ONLY EXCEPTION to this is when scanning and reproducing line art images — for line art, then scan at 1200 dpi.

— JC

Most high quality inkjet printers work best with files in the 300 – 360 dpi range. Some people claim they get good results as low as 200 dpi and some claim to see more detail upto 400 dpi or so.
You can’t use a simple formula because some brands change the size of the droplet as well as the number of them.
Don’t confuse the size you scan at with the size you output at. You may need to scan at a high dpi (1200 – 4000) to allow the image to be enlarged for printing. So a 1200 dpi scan would allow a 4x enlargement at 300 dpi sent to the printer.

Thomas Madsen wrote:

Peter Detheridge wrote:

Can any one please offer me a rule of thumb for calulating scanning resolution for inkjet printing.

I have heard of a rule of thumb that says that you can divide the maximum of the printers resolution with the number of colors in the printer. If it’s a 4 color 1440 dpi inkjet printer, then you need an image at around 360 ppi. If the 1440 dpi inkjet has 6 colors then you only need 240 ppi.

My inkjet printer has 7 colors and the maximum resolution is 2880 dpi. With the above rule of thumb I should use images at around 410 ppi when printing in the printers highest resolution. That’s more than enough in my opinion, but rules of thumbs are, well, only rules of thumbs. 🙂

—
Robert D Feinman

Landscapes, Cityscapes, Panoramic Photographs: http://robertdfeinman.com

Many thanks to all those who have replied. This confirms my thoughts that a value around 300-400 dpi is adequate for my needs.
"Robert Feinman" wrote in message

Most high quality inkjet printers work best with files in the 300 – 360

dpi

range. Some people claim they get good results as low as 200 dpi and some

claim

to see more detail upto 400 dpi or so.
You can’t use a simple formula because some brands change the size of the droplet as well as the number of them.
Don’t confuse the size you scan at with the size you output at. You may

need to

scan at a high dpi (1200 – 4000) to allow the image to be enlarged for

printing.

So a 1200 dpi scan would allow a 4x enlargement at 300 dpi sent to the

printer.

Thomas Madsen wrote:

Peter Detheridge wrote:

Can any one please offer me a rule of thumb for calulating scanning resolution for inkjet printing.

I have heard of a rule of thumb that says that you can divide the maximum of the printers resolution with the number of colors in the printer. If it’s a 4 color 1440 dpi inkjet printer, then you need an image at around 360 ppi. If the 1440 dpi inkjet has 6 colors then you only need 240 ppi.

My inkjet printer has 7 colors and the maximum resolution is 2880 dpi. With the above rule of thumb I should use images at around 410 ppi when printing in the printers highest resolution. That’s more than enough in my opinion, but rules of thumbs are, well, only rules of thumbs. 🙂

—
Robert D Feinman

Landscapes, Cityscapes, Panoramic Photographs: http://robertdfeinman.com