How to change color of borders?

[magnuslar]

Hi!

I'm back at this again, now with Gimp 2.10.6.

When I now try to follow the instructions, I do:
Select none
Lock alpha channel.
THen, however, the "color to alpha" is greyed out.

What am I missing?

Magnus

[Ofnuts]

In 2.10, C2A only works if there is already an alpha channel (in 2.8, this was added automatically). So use Layer>Transparency>Add alpha channel first.

PS: by the way, C2A by definition, alters the alpha-channel, so if the alpha-channel is locked nothing will happen.

[Ritergeek]

Another way to add that alpha channel is to right-click the layer in the Layers dialog. Thinking maybe there's yet another path to adding an alpha channel, l right-clicked the working layer itself. What a nice surprise to find a finger and wrist-pampering pop-up replica of the menu bar right there by my cursor.

[progressneeded]

(02-06-2019, 12:49 PM)rich2005 Wrote: First thing, turn off the selection Select -> None

Then using Gimp 2.8 and reference to screenshots https://i.imgur.com/mUpKIHA.jpg

1. Enable the alpha lock top of the layers dialogue
2. Colors -> Color to Alpha using the default white.
3. With Foreground Color = Blue: click and drag the swatch into the canvas.
4. Reverse procedure, disable alpha lock top of layers dialogue
5. With Background color = White: Layer -> Transparency -> Remove Alpha channel

(02-06-2019, 04:30 PM)Ofnuts Wrote:

(02-06-2019, 03:24 PM)Ritergeek Wrote: Since the option rich2005 suggests does not appear to be available in 2.10, try inverting the selection (Ctrl+i) and delete the white background. The red will go with it. However, that leaves a rather jagged edge. As I look at the original image, I see the selection accurately reflects the current state of the edge. Copying the blue as selected and pasting into a new layer gives the same jagged result.

Here's how to get a smooth, crisp result without backing down to GIMP 2.8:
1) Open the Paths list and convert your existing selection to a path.
2) Convert that path back to a selection.
3) Create a new layer to ensure a clean result
4) Fill the new layer with blue or whatever color.

Color>Color to alpha or the alpha-lock are still there in 2.10. You can also replace C2A with painting in Color erase mode.

I am a noob, and I have the same question about removing borders on images. I have tried following both sets of these instructions, but I am not clear on how to apply some of the steps.

In the instructions Rich2005 posted (thanks for the screen shots), but when I get to step 3 (drag foreground swatch into the canvas, nothing happens. I click and drag, but there are no changes visible. I continued with the steps to check to see if the change would appear when the steps were completed. BUt, I end up with the same image I started out with.

In the instructions by Ritergeek I do not understand step 2. I convert the selection to a path, but do not know how to convert it back to a selection. So, I get no further in the process.

I am still working on understanding all of the terminology and features of GIMP. I appreciate any help offered.

[Ritergeek]

Progress Needed, you are in the right place. I've learned a lot, but still have mountains to climb, and much of what I've learned has come from patient instruction on this forum. Now, for the selection to path and vice-versa question:

With a selection active, the row of icons at the bottom of the Paths dialog has two dimmed icons to the right of the arrows and a third active icon for converting the selection to a path.

When a path is visible with no selection, the two previously dimmed icons are active and the selection-to-path icon is dim. Click the bright red active icon to convert the path to a selection. The path will remain active and visible until you click the eye to hide it.

The reason for converting the initial selection to a path, then back to a selection is to clean up the jagged edge caused by stray color pixels. Your new selection should be crisp and clean.

In general, whatever dialog or menu you see, you'll learn a lot by holding your cursor over icons to see what they do. Following my own advice there, I looked at the Layers dialog and for the first time noticed a dimmed anchor that had never caught my attention. It anchors floating layers, like newly pasted items. Nice to know. I've been clicking the white New Layer icon to do that. Now I have options.

Keep asking questions and learning.

[progressneeded]

(03-20-2019, 02:57 AM)Ritergeek Wrote: Progress Needed, you are in the right place. I've learned a lot, but still have mountains to climb, and much of what I've learned has come from patient instruction on this forum. Now, for the selection to path and vice-versa question:

With a selection active, the row of icons at the bottom of the Paths dialog has two dimmed icons to the right of the arrows and a third active icon for converting the selection to a path.

When a path is visible with no selection, the two previously dimmed icons are active and the selection-to-path icon is dim. Click the bright red active icon to convert the path to a selection. The path will remain active and visible until you click the eye to hide it.

The reason for converting the initial selection to a path, then back to a selection is to clean up the jagged edge caused by stray color pixels. Your new selection should be crisp and clean.

In general, whatever dialog or menu you see, you'll learn a lot by holding your cursor over icons to see what they do. Following my own advice there, I looked at the Layers dialog and for the first time noticed a dimmed anchor that had never caught my attention. It anchors floating layers, like newly pasted items. Nice to know. I've been clicking the white New Layer icon to do that. Now I have options.


Keep asking questions and learning.

It worked! Thank you so much. I have been beating my head against the wall with this (and other things) for a couple of weeks now. I just opened up GIMP last month after having no clue what to do with it for several years. I can't believe how much I have learned in just a few weeks. But, I want to know more.