Helen writes:

I have a photo of a dark red flower against a dark background. I've tried tedious ways to lighten the background without changing the flower,
but the details of the flower are too tiny. So I'm browsing tutorials. Should I
be learning about masks? About layers? A hint how I can approach this?

Selection is what you need to be learning about: you need to selecting the flower and not the background, or vice versa, so that you can run a lightening tool (brightness-contrast, levels, or curves) on the background without affecting the flower.

There are lots of ways of selecting: you could use paths then turn the path into a selection, or you could use select by color or intelligent scissors to make an approximate selection, then use the quick mask to fine tune it and get it perfect.

For any of these techniques (maybe not siox), zoom in a lot so you can see what you're doing and make sure you get all the fine details. That's why these tools are better than something like Lasso select that doesn't let you zoom in.

If you can run the development version of GIMP (2.3), the new siox tool works quite well for flowers against a contrasting background.

A couple other tips: you'll probably want a few pixels of feathering (but you can feather a selection after the fact, from the Select menu), and you'll want to use View->Toggle Selection (ctrl-T) a lot to turn off the selection boundary while you're adjusting the brightness of the background, to make sure you don't get an obvious looking jump at the selection boundary (if you do, try feathering more).

That should give you enough to get you started, anyway. Good luck!

...Akkana

Akkana Peck wrote:

Helen writes:

I have a photo of a dark red flower against a dark background. I've tried tedious ways to lighten the background without changing the flower,
but the details of the flower are too tiny. So I'm browsing tutorials. Should I
be learning about masks? About layers? A hint how I can approach this?

Selection is what you need to be learning about: you need to selecting the flower and not the background, or vice versa, so that you can run a lightening tool (brightness-contrast, levels, or curves) on the background without affecting the flower.

There are lots of ways of selecting: you could use paths then turn the path into a selection, or you could use select by color or intelligent scissors to make an approximate selection, then use the quick mask to fine tune it and get it perfect.

For any of these techniques (maybe not siox), zoom in a lot so you can see what you're doing and make sure you get all the fine details. That's why these tools are better than something like Lasso select that doesn't let you zoom in.

If you can run the development version of GIMP (2.3), the new siox tool works quite well for flowers against a contrasting background.

A couple other tips: you'll probably want a few pixels of feathering (but you can feather a selection after the fact, from the Select menu), and you'll want to use View->Toggle Selection (ctrl-T) a lot to turn off the selection boundary while you're adjusting the brightness of the background, to make sure you don't get an obvious looking jump at the selection boundary (if you do, try feathering more).

I agree with everything here except I'd use a mask instead of a selection. A selection can be a bit too fleeting for a something as tedious as your task.

Eric

On Mon, Oct 24, 2005 at 09:04:15PM -0500, Eric P wrote:

I agree with everything here except I'd use a mask instead of a selection. A selection can be a bit too fleeting for a something as tedious as your task.

it is really an advantage that the people who used gimp-1.0 have over newer users. masks are so much more powerful and long lasting and easier to work with. gimp-1.0 and even gimp-1.2 pushed you into understanding this.

if you would like to really learn the art of computer graphics, installing gimp-1.2 and getting some actual experience with that would be very very helpful for any person who would like to be a graphics expert.

nice advice Eric :)

carol

I agree with everything here except I'd use a mask instead of a selection. A selection can be a bit too fleeting for a something as tedious as your task.

Eric

"tedious" = I probably should have used "detailed". I didn't realize how that came off...

Eric