2007.12.09 15:03 "Re: [Tiff] dpi settings", by Toby Thain

On 9-Dec-07, at 12:44 PM, Graeme Gill wrote:

A rather nugatory remark, especially given the existence of the RATIONAL type in TIFF. I think around the time of TIFF's conception it was not unusual in Europe to specify pixels per centimetre, which might explain the choice of base unit. But really, does it matter?

Only that it seems to be echo'd in some applications (Photoshop comes to mind, although maybe more recent versions have addressed this), and I'm therefore wondering if it's generally understood in the U.S. that cm is not a preferred metric unit, and in practice seems to be falling out of popular usage in the rest of the world.

Is that so? I had not heard, and I've spent my whole life (thank God) in Metricated countries.

But none of that relates to the use of the resolution tag in TIFF except, as you say, as a possible temptation for non-Metric application designers to punt to.

As I say, when specifying metric resolution, pixels/cm has been past European practice (e.g. German imagesetters and scanners, and I think documents such as Karow's Digital Formats for Typefaces). Perhaps someone can chime in with the current practice. I'm sure Adobe is clever enough to honour it, European users would soon complain...

--Toby

Graeme Gill.

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