Digital BW, The Print

Lew,

There is no simple relationship between pixels and printer dots. The camera I use produces 14 bits in each of the RGB channels for each pixel - so each pixel can have 3 x 2^14 states, though most printer software only handles 3 x 2^8 of these.

Ink is basically either on or off - either the printer makes a dot or it doesn't - and images are made by using aggregations of dots in various patterns. Converting between the two systems is a complex matter and some software handles it much better than others. Printer technology also comes into it of course.

Fortunately we don't have to bother too much about it, but simply supply the printer with enough information. For most printers there is little if any difference in supplying files at greater than 300 dpi, which is why this is something of an industry standard.� So all you need is a simple calculation. Divide each of the pixel dimensions by 300 and you get the largest optimum print size.� Though you can make prints quite a bit larger and nobody will ever notice. Use 360dpi if you like, but it really makes very little if any difference.

Currently I use a 32Mp� camera which gives images 7360x4912px. At 300 dpi this will give prints 24.5 x 16.4 inches. I usually make prints around half this size, but going considerably larger isn't a problem.� With the right image you could fill a billboard of your choice.

Peter

My understanding:

A 40mp sensor (for example) produces information for 10mp points of capture due to the fact that the Bayer filter takes groups of 4 input sites (GRGB) to produce a single point of capture record.

If we have a full frame sensor, that would produce (@2:3) a capture of aprox. 2582p x 3873p�

Assuming

1. �that the printer & software editors output 1 capture datum to 1 dot of print (&I understand that this is not necessarily the case)

�-and-

2. that we output to the printer at 360 dots/in

We would have a print of aprox. 7 x 11 inches.

So is the up & down sizing so good that I can produce images of just about any size I want? What's the practical limit on the up side?

-Lew Schwartz