2007.12.08 05:51 "[Tiff] dpi settings", by Ron Croonenberg

2007.12.10 01:43 "Re: [Tiff] dpi settings", by Toby Thain

On 9-Dec-07, at 11:01 PM, Graeme Gill wrote:

Here in the US, the ruler that I have available is marked with inches and centimeters. Are you saying that rulers in the rest of the world are no longer marked with centimeters? If they are not marked with centimeters, then what are they marked with? A ruler marked with millimeters or meters would not be so convenient.

I'm saying that for some time, cm is a deprecated unit, and mm is the preferred unit.

How is it even possible to deprecate a Metric unit? It's only a prefix, and the prefix exists in order to control magnitudes. What evidence is there that centimetres are being "phased out"?

The metrication committee in Australia produced a truly excellent document nearly 30 years ago which covered "preferred" and "non- preferred" units... I don't recall if suffixes were treated in the same way, but I think so. Do Australian standardisation authorities still retain the ability to produce clear guidelines? If so, perhaps you can cite them. But I don't see how this is going to affect TIFF one way or the other.

Yes, many rulers sold here are marked only in mm (although, naturally the markings are at 10mm intervals :-) In some senses this is a subtle distinction, but it's still an irritation to be converting to/from cm, and adds possibly confusion and room for misunderstanding.

For purposes of resolution, I doubt it. Do you find inches more practical in this connection?

It seems natural that centimeters was used since it is easiest to measure the width and height of a computer screen or page-sized object (e.g. sheet of paper) in centimeters rather than in meters or millimeters.

I know what you mean and had a similar reaction myself initially, but it turns out in practice that mm is pretty convenient, especially for paper size, which is where I trip over the cm/mm thing all the time with desktop applications.

I never found that when I was working in pre-press in Australia. It was dpi all the way.

It's a whole number with adequate precision for very many everyday tasks (woodworking is another one that springs to my mind). For grosser scales, a one digit decimal on the meter is often the way to go (ie. 3.1 meters). It's true though that in advertisements, cm is used for TV display sizes. I guess for screen rulings and pixel density pixels/mm isn't so great, although it is something I've standardized on internal in my software (reduces my confusion).

In much official usage (ie. rainfall - when there is any!), mm are what's used.

We're wildly off topic now.

It's hardly uniform amongst the population - when the metric system was introduced here we were taught cm, since they where closer in size to inches, but since then there has been an attempt to standardize on prefixes that are a multiple of 1000, that's been partially successful.

I think that Andrey's observation about technical and non-technical use probably reflects the situation here in Australia

It's not just technical versus non-technical; it's also subject matter. For instance, why do you not question the ubiquity of Imperial INCHES in the pre-press/publishing context (TIFF's home turf)? In a metricated country, isn't that infinitely more confusing than using a metric prefix for a metric unit?

as well to a fair degree, and it will come down to what's currently being taught in schools as to what future trends in popular usage are.

One should only hope the trend of Americanisation there does not lead to abandonment of Metric in toto.


Graeme Gill.

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