Re: [Gimp-user] Printing

[Jay Smith <jay JaySmith com>]

On 01/12/2017 02:21 PM, Richard E Arns wrote:
> Hello
> How do I get Gimp to print larger than postage stamp picts?
>
> I have tried to research on line and just keep going in circles. Give me the good old printed manual over 
> these on line things. Updates online are OK, but I am a book reader and due to injuries I cannot sit at the 
> CPU for long periods of time. Have to keep shifting and walking around often.
>
> Haven't used the program for long but I need a the very least 4x6" and larger when an image is worth printing 
> larger. Got about 3000 4x6" sheets! Use this size for general stuff.
>
> Wanted to print larger today with Gimp, but after three postage stamps and no obvious instruction to print larger, 
> I quit. Grabbed my home  shop made 4x5" film view camera and set off to do some coastal scenes. It's still 
> more challenging and fun than digital! You really have to have a knowledge of light and other conditions to shoot 
> film.
>
> The late and great Ansel Adams saw this coming many years before it all took place...the digital age. But, 
> even he felt that there would always be a place for the film enthusiasts who preferred the challenge. If 
> memory serve me he constructed a huge view camera in his Carmel, CA home that used film sheets that were 
> either 11x14 inches or 16x20 inches in size!
>
> I, as I said, am a reader of books. The computer would not even be in my home if I hadn't needed it back in 
> the '80s when I was still teaching and it became an (expensive) necessity in my life. I am slowly drifting 
> away more and more from digital and back to my old faithful film darkroom. Got enough film, paper and 
> supplies for at least 30 years. And more companies are selling them again. Sorry, did not mean to sound 
> preachy!
>
> Can you tell I was a teacher? Just keep babbling on! Ha!
>
> Best,
> Richard


Richard,

I am a stamp dealer and we use gimp for tens of thousands of stamp 
images, so I should be able to be of some help.

However, first we (all) need to know...

1) What is the source of the images you want to print?  Flat bed 
scanner, digital camera ???

2) At what resolution re the images being captured by that device?
(In Gimp: open an image, in the menu go to Image, then Print Size.  The 
resolution is stated there.)

3) What is the exact purpose/use of the printing?  Please be specific 
(at least I should understand what you are talking about since I have 
been involved in stamp image printing for more than 43 years).

4) What type of device/printer are you printing on and are you printing 
in color or b/w?  Laser printer, ink jet, etc.?  Do you know from that 
device's documentation, what maximum image file resolution they suggest? 
 Try to find that information.

Note that you have specifically stated that you want to PRINT the 
images.  That is a different workflow than what you would do for images 
that you just want to view on screen or on a website.

Note that for stamps you really should be using a flat bed scanner.  A 
camera is usually not worth the trouble for lots of reasons that we can 
discuss separately if you want to.

(Others may find this explanation lacking and may have a better way of 
saying it...)  In general, to print stamp images that look good you 
usually do best with 300 dpi/ppi REAL (not interpolated) resolution AT 
THE PRINTED SIZE.  In other words, if you have a stamp that is 1x1 inch 
and it is captured at 300 ppi (pixels per inch) the image size is 300 x 
300 pixels.  But if you simply enlarge the image (by whatever means) so 
that it is printed at 4x4 inches, then you can't just spread those 300 
pixels over four times the width or length (16 times the total data) and 
expect the result to look good. The 300 ppi/dpi PER INCH means the 
printed image goes from a pixel size of 300 x 300 to a printed image 
pixel size of 1200 x 1200 -- that's 1200 pixels x 1200 pixels of data. 
That data has to come from somewhere -- Gimp can interpolate data 
between two pixels, but it is just averaging the data between each two 
original pixels.  (See below.)

Also, if you are using a camera or flatbed scanner and telling it to do 
the enlarging, it may or may not be interpolating to get the larger 
size.  It depends upon the native dpi/ppi resolution that the device 
captures.  Many flat bed scanners have a setting for the resolution that 
you want to capture.

So, if *I* am going to print an image at roughly four times the size of 
the original object (postage stamp), I will scan at either 1200 or 1600 
dpi.  I will then do my editing, cropping, etc. at that resolution.  I 
will then COPY (SaveAs) the image to a different version (so not to lose 
my original) and ALL IN ONE OPERATION, expand the printing size and 
reduce the resolution.  That "Print Size" dialog mentioned above will do 
that.  As you increase the size, it automatically reduces the resolution 
because it is spreading the same data across a longer distance on the 
paper.  Try it and you will see.  I just doubled one and it halved the 
resolution automatically.  In any case, your goal is to get to the print 
size you want, with a resolution of approximately 300 dpi/ppi.  Much 
more than 300 is completely wasted on most print devices that normal 
folks own.

Also, though others may disagree with me, I strongly suggest that you 
work in a NON-LOSSY file format, such as .tif (TIFF).  If you work in 
.jpg (JPEG), every time you save the image, data is LOST -- do it 
several times and you will end up with a fuzzy mess.  I do everything in 
.tif (TIFF), including printing.  Yes, TIFF files are huge.  If the file 
size is causing you a problem, you can as a separate and last step, once 
your TIFF file is saved, do a SaveAs (to create a new copy/version) to 
.jpg (JPEG) file format.  That is tremendously smaller file size and 
might print faster for you.

We scan to TIFF, edit as TIFF, save as TIFF.  We then use a different 
set of programs and scripts, some of which we developed, to 
automatically create a whole range of sizes of JPEG files for use on our 
website.  We can always go back to the non-lossy TIFF version to change, 
fix, edit, etc. and then automagically re-create the JPEGs.  We do this 
with tens of thousands of stamp images.

What you want to do is a bit different, you said you want to PRINT, 
which involves different concepts and math than on-screen viewing use.

Also, be aware that different publishing or word processing programs 
into which you might want to import images for printing (i.e. Word, 
PageMaker, FrameMaker, etc.), treat different image file formats 
differently.  Some mess with them and re-interpret them and some don't, 
depending upon the program and the file format.  That is a whole 
different subject.

If you have GIMP related questions, please continue this discussion on 
the list/forum.

If you need more stamp-related (i.e not necessarily Gimp), you are 
welcome to email me directly.

Jay Smith