Digital Photo Printing
Maximize Your Photo-Printer Clarity
What is the best PPI image setting for your printer -- 75, 100, 120, 150, 200, 300, ... ?
Download the CameraTrax PrinterTest image and find out! ... It's Free!
What does it measure about printed pixels?
- Monochrome Resolution - How small before they blur together?
- Color Resolution - Does color improve resolution?
- Color Value Discrimination - Can I distinguish Cyan [0 231 255]
from Cyan [0 239 255]?
1) Download the CTPrinterTest.TIF image.
2) Print the image [4x6-in at 600 PPI] on your photo paper.
3) View this print at the distance you will view your photo.
- Monochrome / Color Resolution:
- Blurred printed pixels mean the PPI is too high.
- Blocky printed pixels mean the PPI is too low.
- [Hint: The exact PPI value is not critical so pick a
number which evenly divides into your printer's
reolution -- eg. 1200 DPI / 200 PPI = 6].
- Color Discrimination (at your selected PPI):
- Look at the Cyan, Magenta, Yello and Grey arrays.
- Find the Row that matches your selected PPI.
- Find the Column square with a visible pattern.
- Read the number at the bottom of the Column.
- It is the smallest color value change you can visually
detect at that PPI at the selected viewing distance.
[eg. Cyan '24' would mean a change of 24 in the RGB Green value].
The following table shows the relationship between digital camera image size
and photo-print size depending on the selected PPI. Note that:
- The selected PPI is a good setting for printing your photos
at that viewing distance.
- Ideal print size is determined by your selected PPI and
the pixel dimensions of your digital photo.
- Color Discrimination does not mean the printed color is wrong; it
just shows the printer's color resolution and human
eye's color discrimination limits.
- Note: Because printed color discrimination is usually not even
close to a value of '1', the photo-printer remains the weakest link.
- You don't need a 10 MPix digital SLR to make nice looking 4x6 snapshots.
- Some print sizes are very large -- but so are the viewing distances.
- Printing a 10 MPix image on 13x19 paper and then viewing it from a few
inches will definitly show pixelization. This is expected. The options
are to print it smaller or stand further away.
- Printing a 10 MPix image at 4x6 with 400 PPI is a waste of resolution
because most printers cannot resolve 400 PPI and, at 8 inches viewing
distance, the extra detail would be a blurr anyway.