Re printer rating clarification

[wumply]

Hi:

I need some help in understand fully the following--or a site that will REALLY explain it.

I can use the Canon I850 to ask/explain my question. Canon says it is rated at 4800 dpi for horizontal color resolution and 1200 dpi for vertical color resolution. However PCWorld tests stated that this is a maximum for color AND text, but that actual for color and text is 600 x 600.

So I gather resolution above 600 x 600 is accomplished by computer/printer interpolation--the surrounding area of a given pixel is measured and these pixel areas then are filled in based on the measurements, so that you have a lot more dots per pixel.

1. Is this interpolation done as needed totally automatically anytime I print a color image?

2. OK, final question that baffles me how do all the dots per inch above 600 actually GET printed if the printer is only capable of 600 dpi? Does it take more than 1 pass?

John

[Big Booger]

I'll take a crack at this. I think what it does when you print at higher DPI's, is it takes more sweeps on the paper as opposed to a lower DPI.


Simple example.

600X600 DPI takes 35 sweeps to print one image

Same image 1200X1200 DPI takes 65 sweeps..

I think to get the interpolation is done when you select it in the printer settings. Example: Fine quality slow speed, low quality fast speed... etc... but that is my opinion not a known fact :P


I don't think a printer can print above the rated DPI regardless. So if you have interpolation, and you are printing at 600X600DPI, some of the 600DPI will be used for the interpolation. That is an assumption, again, not a fact.

Perhaps someone with more knowledge about Printer printing methodologies can offer more solid information.

I will say this, no matter how great your printer is, if the image you are printing is low resolution, you're not going to get the sharp color that you are looking for, especially if you start to increase the resolution of the original small image.

In fact if you enlarge a small resolution graphic or image and try to print it, the printer often will make the image look worse by making the pixelation or macros more pronounced.

:D

hope that helps. Sorry I couldn't help you further and offer more definite answers.

[wumply]

BB, I do appreciate that answer and I did learn from it. I never ever even thought it would make more sweeps at higher dpi figures!! Pretty neat, huh? But have you any leads on someone who KNOWS everything about printing methodologies---like the engineer who designs printers?

John

[Big Booger]

http://www.pctechguide.com/12lasers.htm


If that article doesn't key you in on printers no one can! It really is good, with diagrams and loads of info. Though it is geared toward laser printing.

The below page deals with inkjets:
http://www.pctechguide.com/13inkjets.htm

ANd yet another that covers "other Printers"
http://www.pctechguide.com/23oprint.htm

:D