Newbie - Graphics

lodtop@yahoo.co.uk wrote:
> Couple of quick questions.
>
> I want to make a collage of gifs bmps and jpegs. I want it to be A3
> size. I am very new to image processing. I have the image to 300ppi.
>
> The image size is HUGE! 200 MB and I've only done four piccies so far I
> want about sixty!
>
> How do I set this to get a reasonable quality of jpeg image with out it
> going into a massive size?
>
> Also how do I get images in each layer bigger and smaller. I tried
> using the scale layer, but I get a grid that covers the whole layer,
> and when I scale it it makes no diff to the image size?
> At one point I was making the images bigger and smaller, but it don't
> seem to be happenin now.
>
>
> Also can I crop the whole collage later on?
>
> Thanks
>
OK. Let's see if I can help here without leading you astray. A3 =
11.75" x 16.5". At 300 ppi, that results in dimensions of:

3525 pixels x 4950 pixels. This is the size image you should make as a
new image. Save it as, e.g., collage.xcf.

Open an image you want to paste into the collage.xcf. It's important
that you use the .xcf file format so that you can manipulate each pasted
portion of your image independently. If you need to use a different
format for your final version, you can always "save as" later. But if
you don't use xcf while you work on it, then these directions won't
help. .xcf is the gimp's native file format.

Determine how many pixels you want your pasted image to cover out of the
collage total.

Let's say you want to use 350x490 pixels (about 10% of your total final
size, but you can use whatever works for you). What I would do is use
the rectangle selection tool. Set the aspect ration to 350x490 (not the
size!) and then use it to select the part of the image I want for the
collage. Use copy or Cntl-C to copy. Then, before you unselect, hit
Cntrl-n to get a new image. Click OK then hit cntl-v. this will paste
your selection into the new image. Save this image as "scratch.jpg" or
whatever. You're not going to be keeping it. Now resize the image to
350x490. Select all, hit cntrl-C again, then select collage.xcf.

Click Layer > new layer. Hit ok, then paste. Move your pasted
selection on to where you would like it and then hit cntrl-h to anchor,
or open dialogs > layers then click the anchor icon. If you continue to
create a new layer on collage.xcf before you paste, you can then move
each layer independently of the others. If you leave the Layers dialog
open you can do this more easily. Knowing which layer you're on is
very, very important in the gimp! I keep the layers dialog open all the
time. You can also resize layers independently, and use masking to
cover arbitrary parts of the image within the rectangle that you may not
want to show in the final collage.

Given the size of your image, this is certainly going to be a huge file.
I don't see a way around that, even if you use a lossy compression
format like jpeg.

You can now delete scratch.jpg and close your original images. You
should be prompted about saving changes. If you select 'no' then your
original image should be left intact.

Write to me if you have questions and I'll try to help.

lodtop@yahoo.co.uk wrote:
> Couple of quick questions.
>
> I want to make a collage of gifs bmps and jpegs. I want it to be A3
> size. I am very new to image processing. I have the image to 300ppi.
>
> The image size is HUGE! 200 MB and I've only done four piccies so far I
> want about sixty!
>
> How do I set this to get a reasonable quality of jpeg image with out it
> going into a massive size?
>
> Also how do I get images in each layer bigger and smaller. I tried
> using the scale layer, but I get a grid that covers the whole layer,
> and when I scale it it makes no diff to the image size?
> At one point I was making the images bigger and smaller, but it don't
> seem to be happenin now.
>
>
> Also can I crop the whole collage later on?
>
> Thanks
>

If you create an image of the desired size and save it as .xcf, you will
be able to copy and paste your 60 images into this as layers at the size
of the original image. Hmmm. ASCII art needed.

Here's your base image (with the layer dialog showing):


+-----Montage.xcf-------+ +---Layers----+
| | | |
| | |@ Background |
| | | |
| | | |
| | +-------------+
| |
| |
| |
| |
+-----------------------+

You open up one of your source images, Select-> All, Edit->Copy.

Then you select your montage image, and follow these steps exactly:
Edit-> Paste, and for the love of god, DON'T click anywhere on the
Montage Image or in active (white) section of the Layers dialog!!!

You will end up with this:

+-----Montage.xcf-------+ +---Layers----+
| | | |
| | |@ Floating Selection
| | | (Pasted Layer)
| | |@ Background |
| +----------+ | | |
| | | | +--B--B--B--B-+
| | | | +-------------+
| | | |
| | | |
| +----------+ |
| |
+-----------------------+

The inner box in Montage.xcf will have a "marching-ants" selection
around it, and the Floating Selection in the Layers dialog will have a
weird icon like two pieces of paper sitting on top of one another.

At the bottom of the Layers Dialog, click on the "Create New Layer"
button (The one on the left.) The "marching-ants" in Montage.xcf will
change to a static yellow dotted outline, and the Floating Selection
will change to a normal layer with the name "Pasted Layer".

Keep doing this with each image and you will soon have an image with 60
layers and a background. The advantage is that each of your layers will
be the pixel size of the original image, rather than the full size of
your montage - saving memory and disk space.

As an estimate, the above way:
Total size = size of montage images uncompressed + 3508 * 4906 * 3 Bytes
(3 colours, no alpha in the background)

as opposed to 61 full sized layers:
Total size = 3508 * 4906 * 61 layers * 4 Bytes (Each layer = 3 colours +
alpha)

Hope that helps?

Joal Heagney