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having trouble editing an image

Apr 18, 2011, 02:03 (This post was last modified: Apr 18, 2011 02:13 by create90212.)
Post: #1
having trouble editing an image
hi guys
I don't know much about gimp. I can do simple stuff, but i am having trouble editing a picture for some reason.
I downloaded this free template at
h**p://www.templatescreme.com/free-website-grand-host

if you look in the images folder, there is a picture called nav-left1.gif

I am trying to make everything that is orange, blue.
I have edited pictures thousands of times, but this one, the color wont change. its like someone locked it to stay orange.
can you take a look and tell me whats going on? how can i unlock it? thanks

edit: I just attached the picture, didnt know you can attach files here.


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Apr 18, 2011, 03:15
Post: #2
RE: having trouble editing an image
Without knowing exactly how you were trying to edit the image its kind of hard to say exactly, but I'm going to go out on a limb here and guess that its because you're staying in indexed mode. Gif files don't use the whole array of 16.7 million colors that most other images use. They have what is called an indexed palette, meaning that there are 256 slots for different colors. You can pick any color you want for each slot, but then you are limited to those colors and no others. Your image has a palette that is full of different shades of orange and no blue at all.

To edit your gif image try opening it, then go to Image>Mode, and select RGB. Now you should be able to edit the colors as you like. Select a brush and set the foreground color to whatever shade of blue you like. Now change the brushes mode from Normal to Hue. Paint over the image and it should change from orange to blue but still keep the shadings of light and dark.

Now, when you want to save it you can go two ways. You can save it as a PNG, which means you won't have to worry about color palettes. Or, if it really needs to be a Gif for some reason, simply go back to Image>Mode and change it back to Indexed. Check "Generate optimum palette" and select 256 as the maximum number of colors. Then save it as normal and you should be all set!
   

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Apr 18, 2011, 04:46
Post: #3
RE: having trouble editing an image
(Apr 18, 2011 03:15)Virago Wrote:  Without knowing exactly how you were trying to edit the image its kind of hard to say exactly, but I'm going to go out on a limb here and guess that its because you're staying in indexed mode. Gif files don't use the whole array of 16.7 million colors that most other images use. They have what is called an indexed palette, meaning that there are 256 slots for different colors. You can pick any color you want for each slot, but then you are limited to those colors and no others. Your image has a palette that is full of different shades of orange and no blue at all.

To edit your gif image try opening it, then go to Image>Mode, and select RGB. Now you should be able to edit the colors as you like. Select a brush and set the foreground color to whatever shade of blue you like. Now change the brushes mode from Normal to Hue. Paint over the image and it should change from orange to blue but still keep the shadings of light and dark.

Now, when you want to save it you can go two ways. You can save it as a PNG, which means you won't have to worry about color palettes. Or, if it really needs to be a Gif for some reason, simply go back to Image>Mode and change it back to Indexed. Check "Generate optimum palette" and select 256 as the maximum number of colors. Then save it as normal and you should be all set!

hi
thanks for the help. I did exactly what you said and I got the same result as you. the only problem is, I selected the color 091b4e (which is dark blue) for my blue, but my blue came out exactly like yours (light blue).
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Apr 18, 2011, 19:58 (This post was last modified: Apr 18, 2011 20:00 by ofnuts.)
Post: #4
RE: having trouble editing an image
(Apr 18, 2011 04:46)create90212 Wrote:  thanks for the help. I did exactly what you said and I got the same result as you. the only problem is, I selected the color 091b4e (which is dark blue) for my blue, but my blue came out exactly like yours (light blue).
The hue mode only transfers the hue, so if you want a color that has, in HSV, besides a different hue, a different saturation or value, things are a bit different. "Color" mode transfers hue and saturation and leaves the value alone. If you want to change the value as well, playing with brush modes won't help much because the painting has to be very accurate (the "value" channel is where all the detail is), so a pre-selection is in order, and once you have that you can as well bucket-fill.

Another solution would be to add a new layer below with the target blue color, and use color-to-alpha and color picking the orange to make current orange areas transparent. But color-to-alpha may be a bit blunt...

PS: Both images above do not display as links for me...

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Apr 19, 2011, 01:02
Post: #5
RE: having trouble editing an image
(Apr 18, 2011 19:58)ofnuts Wrote:  The hue mode only transfers the hue, so if you want a color that has, in HSV, besides a different hue, a different saturation or value, things are a bit different. "Color" mode transfers hue and saturation and leaves the value alone. If you want to change the value as well, playing with brush modes won't help much because the painting has to be very accurate (the "value" channel is where all the detail is), so a pre-selection is in order, and once you have that you can as well bucket-fill.

Yeah, I'm still working on understanding the whole HSV thing. I thought I had it working until I tried changing the shade of blue. I tried Color mode, Saturation Mode, and just about all the other modes as well.

(Apr 18, 2011 19:58)ofnuts Wrote:  Another solution would be to add a new layer below with the target blue color, and use color-to-alpha and color picking the orange to make current orange areas transparent. But color-to-alpha may be a bit blunt...

I just tried this and couldn't get it to work right. I was getting some strange colors that weren't even close to the blue I was aiming for. I originally tried a variant of this using a layer mask derived from an inverted gray-scale version of the original layer. It always seemed to make the blue color much lighter than what I intended.

(Apr 18, 2011 19:58)ofnuts Wrote:  PS: Both images above do not display as links for me...

That's because they aren't links, they're the full size images. Guessing from the file name I'm assuming that it is the left end cap of a web site navigation bar. I've been working on these at about 500% just to get it to were I could see what I was doing.

So, I guess I get about half a cookie for figuring out to change from palette to RGB mode in the first place. But is there any way to change the color of this to the specific blue that create90212 was looking for (091b4e) while still keeping the gradient intact?

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Apr 19, 2011, 08:53
Post: #6
RE: having trouble editing an image
(Apr 19, 2011 01:02)Virago Wrote:  That's because they aren't links, they're the full size images. Guessing from the file name I'm assuming that it is the left end cap of a web site navigation bar. I've been working on these at about 500% just to get it to were I could see what I was doing.
Aw, should have given a bit more than a cursory look then Smile

(Apr 19, 2011 01:02)Virago Wrote:  So, I guess I get about half a cookie for figuring out to change from palette to RGB mode in the first place. But is there any way to change the color of this to the specific blue that create90212 was looking for (091b4e) while still keeping the gradient intact?
Of course not... because we have a gradient with 3 colors, and we need 3 colors for a replacement... If you use the Pointer dialog on the image, you see two successive gradients implemented with three colors:

RGB(244,162,66)/HSV(32,73,96) to RGB(249,203,99)/HSV(42,60,98)
and
RGB(244,162,66)/HSV(32,73,96) (again) to RGB(240,128,42)/HSV(26,82,94)

(note that given Gimp's advanced gradients, this can be implemented as a single gradient with two segments).

So what we want now is to emulate the "effect" with another gradient based on the color suggested by the OP... but:

1) we don't know which of the three colors should be the base
2) this color could even be the middle color of one of the two gradients
3) the requested color is very dark and the effects aren't the same....

Here is a possibility:
[attachment=309]

So the OP need to look for himself what would give the best effect along the lines:

Base color: H,S,V
First gradient: (H,S,V) ->(H,S-50,V)
2nd Gradient: (H,S,V) -> (H,S,V-30)

In other words, the first gradient reduces saturation, the second reduces the value.

One the gradient has been found, changing all the images requires by the web site becomes very easy....

Personally, although it is very frequent these days, I don't like the blunt transition in the middle, and I prefer the rounder effect given by

(H,S,V)->(H,S-x,V)->(H,S,V-y), for instance:
[attachment=311]

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Apr 19, 2011, 13:50
Post: #7
RE: having trouble editing an image
(Apr 19, 2011 08:53)ofnuts Wrote:  Of course not... because we have a gradient with 3 colors, and we need 3 colors for a replacement...

I suppose somewhere in the back of my mind I knew that, I just didn't want to admit it. After seeing what you did with Hue and Saturation modes in that other thread with the fish, I was just looking for a magic wand to wave over the image. Maybe I should submit that as a feature request for a future version, but I guess we're just not there yet. Smile

Thanks for all of your help on this Ofnuts, it is greatly appreciated!

And Create90212, I hope this answers all your questions and gives you the info you need to design your image the way you wanted it.

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Apr 19, 2011, 15:24
Post: #8
RE: having trouble editing an image
Many questions asked in this kind of forum are skewed from start. The OP has a problem, thinks of a solution, but this solution leads to another small problem, to which a solution is found, but there is another little problem with that, so he seeks help... and the question that shows up here is the 3rd- or 4rth-level one. Very often if the OP had originally stated the right question, he would have found the answer without asking (I'm not singling out the OP, everyone does that, I just do that less often with Gimp than with other software I deal with...)

So very often the questions asked here aren't the good ones and some mind-reading is required... I just hope I've been correct here, but only the OP can answer that Smile

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