font sizes

[jimbir]

PSP gives me two choices for font size. points or pixels. The way I understand it, points are based on 72 points per inch. Font size of 1/4 inch equals 18 points. Pixels are based on what ever the pixels per inch value was when the image was created. Font size of 1/4 inch on an image created at 300 pixels per inch would be 75. I generally work with points. The problem I'm having is, when I print an image at a 1:1 scale, the fonts measure smaller then the 1/4 inch in the example above. Correct me if I'm misunderstanding the size correlation between pixels, points, and inches.

Thanks. Jim B.

[LeviFiction]

The conversion from points to pixels is based on the resolution, yes. And your math works out.

The problem is points do not refer to individual letter sizes. Both "A" and "a" are the same font size. The size refers to the area surrounding the letter. (That is a horrible description) You'll also notice that different font faces at the same point size don't work out to the same printed size.

[jimbir]

Am I to understand that there is some space around the letter that does not print. Say a letter that is 18 points may have 2 or 4 points above and below and prints an actual 14 or 16 points high. any way to calculate this blank space?

[LeviFiction]

Not really, just eyeball it. The bounding box, for example, allows for letter tails and other things so even that isn't a good measure for the point size.

There is seriously no requirement for font designers to make their characters fit a certain amount of space. Some "a"s are more squished than others at the same point size because they were designed that way. Calculating the space around it at a set point size would have to be done on a font face by font face basis. That's just too much.

The best way I can recommend, is to set up a measure or ruler of some sort if the size of the character absolutely has to be 1/4th of an inch.

For example, if you know that you need the letters to be 75 pixels high, make a 75 pixel high line. (You can use the pen tool) Then find a point size that makes the word match that height.

With Times New Roman, using capital letters I found that it closely matches a 75 pixel line at 28 points. That's ten points higher.

[jimbir]

Thanks for the help. I took the broad axe approach and printed a sheet with lines of text at different point settings then measured them with a ruler. I now have a reference to go by.

Jim