GIMP Version: 2.8
Operating System: Windows
OS Version: XP - SP3
GIMP Experience: Basic Level

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i have been toying round with quick mask mode to make selectionsi have changed the eye color on a picture by making the iris on its on transparent layer. how do i nge the color of the eye a second time after closing because i dont like the color? basically, how do i reset the eye to original color with out losingthe selection so i can change the color of the eye with out having a colorized selection control the next color?

thanks

Whenever you are working on a photo its always good practice to make a duplicate layer and work on the duplicate, that way you can compare changes made to the original and in your case easily duplicate the original again if you want to try something else.

The other thing I tend to do is if I have spent a long time making a selection around an object I will always when finished go Selection>Selection to Path, this will save your selection as a path, so even if you delete your selection and decided you need it again its there as a path, also paths save in the xcf file so will always be there even if you close and reopen gimp.

The undo stack is not saved to file so once you have closed the file you can't go back.

One solution it to import the original image as a new layer in the image where you have the selection ("File/Open as layers").

But you can copy the selection between two images:

First method:
- In the source image: "Select/Save to channel" (this saves you selection as a "channel")
- Open the "Channels" view, make sure your saved selection is selected (it should be by default) and "Edit/Copy"
- In target image: open the Channels list, and create a new channel. Click on the eye icon to make it invisible.
- With the new channel selected: Edit/Paste: this creates a "Floating selection" that you see at the top
of the Layers list
- Layer/Anchor Layer: the Floating Selection is moved to the channel
- Right click on channel and "Channel to selection"

2nd method:
- In the source image: "Select/Save to channel"
- Open the "Channels" view, click and drag the saved selection to the target image and drop it on the canvas
- this creates a B&W layer on the top of the stack
- open the Channels list, right click on any of the R,G,B channel and "Channel to selection"
- delete the top layer.

No, it doesn't... what it saves is the locus of the pixels where the selection is at 50%. If you have a partial selection you have lost it. And even with a binary selection it's not too good:

- create new image with white background
- make a wiggly selection with the free hand select
- bucket fill selection with black
- Select/To path
- Select/From path
- add another white layer, and bucket fill selection with black
- put the top layer in difference mode, hide the ants (Ctrl-T),and observe the nice ring indicating where the two selections aren't equal.

Use Select/Save to channel instead

all right. i guess i have some more toying around to do so i can see how to accomplish all the methods. I have noticed that a few things in this program are differnt than what i am used to. I am used to photoshop version 7. hahaha. like way oldschool. Here is one difference i noticed. if i open a jpg in photoshop 7, i can select part of it and hit delete. now it will show some transparency under it. With the gimp, it wont delete it. Also, im not used to always having to add an alpha chanle to make things transparent. in PS&, it was automatic.. or at least i remember it that way. haha

thanks

You can always add an alpha channel after loading the JPG. One explanation of the absence of alpha channel is that if you load a JPG you are likely to save/export it as a JPG later, and you'll lose the transparency. So not adding the alpha channel prevents some bad surprises.

I totally agree with you on Channels, I use them all the time.

I understand how it might throw you off. Read all the way through, Chapter 8.1. Introduction to Layers in Gimp Help. Take special note of the section, 'Presence or absence of an alpha channel'.

Offnuts - thanks for the advice on saving to channel, always wondered what the point of that was.

oh wait, duh. i knew that jpgs didnt save transparents. haha. i just have to remember to add it because some jpgs i convert to transparent images becuase the original image is jpg and thats all i gots. haha

I have a "beginner" question on method 2. Say I have two images open in Gimp (the thumbnails are at the top). I want to drag-and-drop a channel selection mask from the first one to the second. When I drag my channel to the second thumbnail at the top, the thumbnail becomes highlighted, and it's canvas shows, but if I drop my channel on this canvas, it isn't moved to the layer list.

According to the Gimp manual, I should be able to do the same thing with layers, but my results are the same with layers.

I know this is just a basic misunderstanding on my part, probably about how I'm selecting the second image. I should add that drag-and-dropping a channel to it's own canvas adds the B&W layer just as you described. Any help would be appreciated.

It is not a misunderstanding, there is a bug report for it. Alternative solutions are presented in this thread.

Thanks, I appreciate that. I was sure it was me.