change colors

[bnmjeff1]

I have a Jpeg of a line drawing. There are blue and red lines. I want to fill in the blue sections and change all the lines red and blue to black so I can make a Cricut cut file from it. Is there an easy way to do it?? I know it's a broad question....

I've attached the JPEG...


Jeff

[denzjos]

Use Colors / Map / Color Change: just select the line color (blue / red) with the 'From Color' eyedropper and the color will become black (the default 'To Color' 2 is black, you can change it by clicking on the color)

   

[bnmjeff1]

Thanks for the reply....I have tried quite a few times and the color of the line does not change...my Color Exchange box looks just like your with the exception of the black line through your example...

[rich2005]

(04-09-2025, 05:04 PM)bnmjeff1 Wrote: I have a Jpeg of a line drawing. There are blue and red lines. I want to fill in the blue sections and change all the lines red and blue to black so I can make a Cricut cut file from it. Is there an easy way to do it?? I know it's a broad question....

I've attached the JPEG...


Jeff

Hmm...looks like a bit of editing has already been done. Some nasty remnants of erasures maybe

You can color exchange or even color select and fill, There are areas where the blue obviously overlaps the red line and some repair needed.

However, looks to me like that was originally a vector image. You can prepare the lines on a colour basis and center-line trace using Inkscape. I think this comes under Is there an easy way...NOT

The svg paths from Inkscape go back into Gimp and then you can stroke Edit -> Stroke Path at whatever size you need, for an outline and fill Edit -> Fill Path for solid areas. 

Sooner or later you will probably have to get into using Inkscape so image attached as an example.

[bnmjeff1]

Wow...that was quick (From my point of view!) and yes there was some clumsy deleting on my part....lol

Thank you for doing that for me...I will take a look at Inkscape...thank you for showing it to me....

Jeff

[rich2005]

OK, I was half watching TV so not much saved. Some clues as to procedure.

You can colour select one of the colours. That will Copy then Paste -> As a new image.
It has a transparent background so removing the alpha channel leaves colour on white.
Edit -> Generic -> Dilate grows the coloured line. A couple of times to give a reasonable size.
A bit of hand painting repair for any missing sections.
Colors -> Color-to-Alpha removes the white background.
In linux I can drag that from Gimp into Inkscape. Otherwise export as a png and open in Inkscape.
In Inkscape, I can centerline trace (one path per section of line) the image.
Save that as a svg file then in Gimp right click in the paths dock to import the path. Stroke or fill as required.

[bnmjeff1]

(04-09-2025, 07:59 PM)rich2005 Wrote: OK, I was half watching TV so not much saved.  Some clues as to procedure.

You can colour select one of the colours. That will Copy then Paste  -> As a new image.
It has a transparent background so removing the alpha channel leaves colour on white.
Edit -> Generic -> Dilate grows the coloured line.   A couple of times to give a reasonable size.
A bit of hand painting repair for any missing sections.
Colors -> Color-to-Alpha removes the white background.
In linux I can drag that from Gimp into Inkscape.   Otherwise export as a png and open in Inkscape.
In Inkscape, I can centerline trace (one path per section of line) the image.
Save that as a svg file then in Gimp right click in the paths dock to import the path. Stroke or fill as required.

all that while half watching TV...impressive..thanks for the detailed steps....

Jeff

[rich2005]

Only half watching. All very depressing at the moment. However, some Terry Pratchett quotes for today to bring things into perspective

"Real stupidity beats artificial intelligence every time"

"The truth may be out there but the lies are inside your head"

"Taxation is just a sophisticated way of demanding money with menaces"

[teapot]

Here's a different method for which you will need gimp (I used a 2.10 version) and also G'IMIC Qt which you can get as a plugin for Gimp. If you haven't got G'IMIC I'm sure someone will tell you how to get it.

Open your 'flowery flowers template.jpg' in gimp.
Duplicate the layer, because keeping the original is always a good idea.

Make a black and white layer of the flowers, this is your lineart layer:
    On the duplicate layer do:
        Colours -> Desaturate -> Desaturate
            Mode: Luma
        Colours -> Curves
            Drag the bottom left of the line to the right until the greys look black, see the red arrow in my example attached below.

Make a colour spots layer:
    Make a new transparent layer:
        In the new transparent layer:
            With the pencil tool draw black blobs/spots in all the areas you want to fill with black.
            With the pencil tool draw some red spots/lines in the background you don't want to fill with black.
    See the my attached colour spots below for an example.

Turn off the visibility of all layers except for your lineart layer and colour spots layer.
The colour spots layer should be above the lineart layer in the layer stack.

Use gmic colourise lineart to colour in the flowers:
    Filters -> G'IMIC Qt -> Black & White -> Colorize Lineart (Propagation)
        Layers ordering:
            Input layers: Color Spots + Lineart
            Output layers: Extrapolated Colours + Lineart
            Extrapolate Colors as: One Layer per Single Color
            Smoothness: 0.05
        Input / Output:
            Input layers: All visible
            Output mode: New layer(s)
            Preview: Mode: 1st output (default)

When G'IMIC Qt has finished you should have three new layers from top down in the layer stack:
    The background all coloured red
    Areas of flowers filled in black on a transparent background
    Lineart

Turn off visibility of all layers except:
    Areas of flowers filled in black on a transparent background
    Lineart

That's the result, mine is attached below, you can export it e.g.
    File -> Export
Or if you want it as one layer:
    Layer -> New from visible
Or you could merge the two layers.

[denzjos]

(04-09-2025, 06:51 PM)bnmjeff1 Wrote: Thanks for the reply....I have tried quite a few times and the color of the line does not change...my Color Exchange box looks just like your with the exception of the black line through your example...

I could'n see the drawing yesterday. So it's quite simple to get a nice result. My way to do it:
First a some time consuming thing (little than 5 minutes)
Erase the black / grey things with the 'Select by Color Tool' (set the Threshold to 45 )  - select and delete them all
Unselect all : Select / None
Convert the drawing to BW : Colours / Desaturate / Desaturate
Darken the result: duplicate the layer a few times with the layer mode 'Multiply' until you get a real black drawing (
Make a new layer ' New from Visisble' and delete all the other layers
Connect the few gaps with black lines, use the 'Pencil Tool'
Blur the result : Filters / Blur / Gaussian Blur (value 3 or 4)
Darken the result: duplicate the layer a few times with the layer mode 'Multiply' until you get a dark black drawing
Make a new layer ' New from Visisble' and delete all the other layers
Select the white outside with the 'Fuzzy Select Tool' (value 40) and invert the selection : Select / Invert 
Fill the selection with with black, use the 'Bucket Fill Tool'
Unselect all : Select / None