need help re correct sequencing of project

[boash21]

[attachment=12856]
New to gimp and working in to it bit by bit and getting dead ends partly I think doing things in the wrong order.
In the attached jpg I need to
1. select the round plate, rotate it slightly, and separate it from the background
2.fill the background with a solid colour
3. select a square around the plate slightly bigger so it sits against the coloured background.
4. set it up to print 8x8” at good resolution.
I suspect I am making a fairly simple task more difficult by doing steps in the wrong sequence.
Appreciate any help.  
eg get crawling ants around both the plate and background and can't do anything with it

[sallyanne]

I tell you why you think you get crawling ants around both - they are on different layers. If you select one (alpha to select - or select all) it will get crawling ants. Otherwise it should have just black & yellow dashes around it if the layer is selected. Otherwise if the lower layer has a selection in the middle inside the size of the top layer - the selection will show through that layer. You can get rid of any selections you dont want by clicking on select (from the top menu) and none.

If your plate is round use the ellipse select and copy it onto (as a new layer) the background of your color choosing, making sure it is 300 ppi when you make the background. Make a transparent layer above your background and below your plate. Make sure you have a horizontal and vertical guide at 50% each and centre your plate on the cross section. Using the rectangle select, in the tool options click on expand from center and starting at the intersection of the guides make sure your size in the tool options box is the same width as the height and you should have a proper square then.
Stroke this selection, fill it or both (However you want to go about it).

Maybe someone knows a quicker way to go about it.

[denzjos]

Select the plate with the "Ellips Select Tool'  (marching ants) and press 'enter' on the keyboard
Invert the selection:  'Select / Invert' on the gimp menu
Fill the background with a color, use the 'Bucket Fill Tool'
Then 'Select / None' to remove the marching ants
Select the square you want with the 'Rectangele Select Tool' (marching ants)
Then 'Edit / Copy' and 'Edit / Paste As / New Layer
Set the original layer off

[boash21]

(12-30-2024, 04:24 AM)boash21 Wrote: New to gimp and working in to it bit by bit and getting dead ends partly I think doing things in the wrong order.
In the attached jpg I need to
1. select the round plate, rotate it slightly, and separate it from the background
2.fill the background with a solid colour
3. select a square around the plate slightly bigger so it sits against the coloured background.
4. set it up to print 8x8” at good resolution.
I suspect I am making a fairly simple task more difficult by doing steps in the wrong sequence.
Appreciate any help.  
eg get crawling ants around both the plate and background and can't do anything with it

---

(12-30-2024, 09:57 AM)boash21 Wrote:

(12-30-2024, 04:24 AM)boash21 Thank you very much for that quick answer , I certainly was doing a lot of blundering around, will give it a go tomorrow Wrote: New to gimp and working in to it bit by bit and getting dead ends partly I think doing things in the wrong order.
In the attached jpg I need to
1. select the round plate, rotate it slightly, and separate it from the background
2.fill the background with a solid colour
3. select a square around the plate slightly bigger so it sits against the coloured background.
4. set it up to print 8x8” at good resolution.
I suspect I am making a fairly simple task more difficult by doing steps in the wrong sequence.
Appreciate any help.  
eg get crawling ants around both the plate and background and can't do anything with it

[boash21]

(12-30-2024, 07:50 AM)denzjos Wrote: Select the plate with the "Ellips Select Tool'  (marching ants) and press 'enter' on the keyboard
Invert the selection:  'Select / Invert' on the gimp menu
Fill the background with a color, use the 'Bucket Fill Tool'
Then 'Select / None' to remove the marching ants
Select the square you want with the 'Rectangele Select Tool' (marching ants)
Then 'Edit / Copy' and 'Edit / Paste As / New Layer
Set the original layer off

---

Thanks again sallyanne and denzjos, have progressed to the last step I think.
Is there a relationship between the canvas and print size. eg. do they need to be the same?

[denzjos]

(Yesterday, 02:07 AM)boash21 Wrote:

(12-30-2024, 07:50 AM)denzjos Wrote: Select the plate with the "Ellips Select Tool'  (marching ants) and press 'enter' on the keyboard
Invert the selection:  'Select / Invert' on the gimp menu
Fill the background with a color, use the 'Bucket Fill Tool'
Then 'Select / None' to remove the marching ants
Select the square you want with the 'Rectangele Select Tool' (marching ants)
Then 'Edit / Copy' and 'Edit / Paste As / New Layer
Set the original layer off

---

Thanks again sallyanne and denzjos, have progressed to the last step I think.
Is there a relationship between the canvas and print size. eg. do they need to be the same?

Some information about that : https://www.gimp-forum.net/Thread-Image-size-in-Gimp

[rich2005]

(Yesterday, 02:07 AM)boash21 Wrote: .....snip....
Is there a relationship between the canvas and print size. eg. do they need to be the same?

Check out the link that denzjos gave

In brief: The canvas size in Gimp is in pixels, You can see the size in the Gimp title bar. The print resolution will determine the print quality depending on the pixels-per-inch (ppi sometimes called dpi) that you set.

A simple example:
A 300 x 300 pixel image when printed at 300 ppi prints an image 1 inch x 1 inch. Small print but good quality.
the same image
A 300 x 300 pixel image when printed at 50 ppi prints an image 6 inches x 6 inches. Larger print but poor quality.

[boash21]

Thanks rich2005,I re read that post and 2nd time round a bit more sunk in as it does. To get my image to a print size of 8x8in x300dpi I had to upscale the image. Looks ok, will find out when I print it.

[rich2005]

(Today, 03:50 AM)boash21 Wrote: Thanks rich2005,I re read that post and 2nd time round a bit more sunk in as it does. To get my image to a print size of 8x8in x300dpi I had to upscale the image. Looks ok, will find out when I print it.

No.  You still do not get it. What matters is the size of the image in pixels.  For 8" x 8" image and 300 ppi you need to start with a canvas size of 2400 x 2400 pix.  

Upscaling the image is just equivalent to reducing the print definition and you do not get any better quality.  It is another case of "What Goes In Comes Out"

Edit: You can leave the scaling to the printer. It will be as good as you scaling. 40 second example: Gimp 2.10.38 (linux) 
https://i.imgur.com/GcIoFAb.mp4

Circumstances where you might need to scale yourself, is sending the image to a commercial printer. They might insist on 300 ppi (or close) In that case it is up to you to make the image as good as possible, using NoHalo interpolation to upscale, sharpen the image...etc