Low DPI when saving

FF outputs images at 72 DPI. You can fix this in Photoshop losslessly by going to Image / Image Size and unchecking the resample box, then changing the DPI as needed and saving the file. There is more about this here.

Personally I think that the DPI should be passed through unchanged, but this has been known for a long time and probably will not be changed.

I don't have Photoshop, so I can't run FF as a plugin. (I have Serif PagePlus, and I think I've read that one of the sister programs -- Draw or Photo -- can run FF as a plugin, but last time I asked on the board nobody replied that they had successfully used the two programs together.)

PhotoFiltre seems to automatically resample when one increases the DPI (there is a resample box that I can't uncheck; all I can do is change the type of resampling being done).

To make a very long story short, I have a black-and-white enlarged photographic copy of an old photograph. I scanned it and reduced the size to what I need (about 3 inches across).

But I thought it would look more old-timey if I used one of the sepia filters in FF on it, and, after trying many filters out, I found one that I like (Retro Color Multitone, if anyone is wondering).

So, what should I do? Should I get the super-sized original scan (which is off on a different computer) and try to run it through FF? Or should I take the smaller one, resize it to 300 DPI in PhotoFiltre, and hope for the best? It actually looks good to me, but I'm concerned that it might not print well.

To simplify, the only true resolution of any graphic image is the image width and height. The DPI is just an instruction or advisement to the printer driver. Most printer drivers allow you to alter DPI at print time with options to change the size of the print (Fit to Page, % Scaling, etc).

Here is a helpful link about changing DPI.

GIMP is a good option for changing DPI (without re-sampling) and is a fine graphic application on multiple platforms. And it is free. Only downside, don't think you can use FF as a plugin with GIMP.

And for Windows, quite a few solutions exist to change DPI without resampling:
http://superuser.com/questions/607663...f-an-image. paint.net looked like a good simple solution.

Well, even with using GIMP for the one picture that I thought might be problematic and Serif PagePlus saying that all the picture elements were at 300 DPI or higher, the printer still flagged something as being low DPI. I am going to get a proof done and hopefully no problem will be noticeable to the eye.

Hmm . . . I'm probably not stating something clearly (or I don't know something). For print, I needed an image that was approximately 3 inches across and 300 DPI (thus, it needed to be approx. 900 pixels across). I opened the image in FF, ran it through a filter, and saved the resulting image. When I opened it in PhotoFiltre Studio, it said it was now 72 DPI.

Now, here is where I may have gotten confused -- I thought it said that it was 72 DPI and still 900 pixels across, which I think wouldn't have printed well.

When I downloaded GIMP and opened the image, it allowed me to increase the DPI without resampling (I hope it worked; I followed directions I found online). Then I was back to 3 inches/900 pixels across and 300 DPI.

But I could be confused about how DPI works; I kind of ended up working with images by accident and am learning as I go along.

But if the dots are "further apart," the image will not look good when it is printed! I had this problem frequently when I was editing a local publication -- someone would send me a low quality picture (at a low DPI) and insist that it would have to be printed because that was all they had. I'd do the best I could with it, but the pixelated, blobby, blocky pictures that sometimes resulted were far, far from ideal.

If I do have an image that is at too low DPI AND too small in the dimensions -- say, 200 DPI and 2 inches/400 pixels across and I need 300 DPI and 4 inches/1200 pixels, is there a magic way to make that happen? And the resulting image look good in print? I've been able to "fudge" somewhat upon occasion but would like to do better.

The picture printed just fine