GIMP Version: 2.10.12
Operating System: Windows
OS Version: 10 64 bit
GIMP Experience: Basic Level

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I create advertising for my job, and I regularly reproduce historical-looking documents as ads. For a background image, I've been trying to replicate the look of old vellum without much success. I have found a couple of filters that sort of work, but not quite in the way I need. Vellum ages in a very complex way, so I can't just dash off a couple of layered colors and call it a day (every vellum/parchment guide I've found online does this, and it always looks cheap). It has to match the item that I use as the foreground and/or image. So, questions towards that goal:

The Plasma filter replicates colors and shading in the way that I'd like for the background, but obviously the colors are not right. How do I tell the filter to only pick specific colors or from a specific range? Failing that, how do I write a custom filter to do what Plasma does, but with my colors? (I'm not averse to coding).

How do I add pixels of a color I pick to a background image, in random places? (Basically, how do I get the brush to place pixels at random places within the selection, ie a randomized sprayer).

And ultimately, is there a way to get the program to analyze an image and pick out the colors being used, or better yet, to replicate them in a random way, or at least using the filters?

Thanks in advance.

Hi cabel, Welcome to Gimp Chat. I can't answer your questions but I'm sure that someone here will do it. Luck!

Is it possible for you to post an image, or link to an image, of what you are looking to create? On Bing, I searched "vellum texture" and "pergamena texture" (more results for pergamena than vellum), and there is an extremely wide spectrum of "aging." On DeviantArt, there are also a couple of vellum texture packs, as well as a "foxing overlay." Is there one image that you prefer? It might be a good starting point.

I have a somewhat similar request at GIMP Learn, regarding mottled paper. Once you post an image, someone will surely be able to help.

I work for the US government, so I can't just use other people's images unless they're expressly in the public domain, so texture packs are out for the most part.

I've attached an example of a document on vellum (it won't let me paste it in here, for some reason) here:



What I want to do is basically to erase all the text from that document so I have blank vellum. That can be via sampling the colors and texture and painting, creating a series of filters/layers to replicate it, or any other method other than cloning it (it never looks right when it's cloned).

You can get rid of the text by blurring the image. Gaussian blur, about 5 or 6.

Excellent suggestion for documents that are only text, but what about ones that have images (which is mostly what I work with)?

Example:

I've never seen a vellum page but...........
if you remove the text to make a blank vellum page isn't that the same as removing images to make a blank vellum page?

I would get myself a collection of blank vellum pages. Then you could rotate them, dirty them up, transform them horizontally and overlay them on each other to get that one of a kind look.

Just a quick go from scratch.



(If anyone wants some light reading: Text of Magna Carta)

Care to share the technique?

Your latter suggestion is one of my possible courses of action - how would I go about "dirtying them up?" Part of my question was directed at that

1) Assume just shades of brown.

2) Set FG and BG to light brown and dark brown

3) Ensure Gradient Tool is set to FG to BG (a different gradient with more colours can be used if required)

4) Filters > Render > Noise > Plasma

5) Colours > Desaturate > Desaturate

6) If required: Colours > Auto > Stretch Contrast

7) Colours > Map > Gradient Map

1. New A4 portrait.
2. Bucket fill new color = eccdaf.
3. Change FG/BG back to Black & White.
4. Layer > New Layer… > Name it Noise and fill with Transparency. OK.
5. Filters > Render > Noise > Solid Noise...
6. Adjust settings as required. Press OK.
7. Adjust opacity of Noise layer as required.
8. Image > Flatten Image.
9. (optional) Filters > Noise > HSV Noise... Adjust settings as required.
10. File > Open as Layers...
11. Load "Bump map paper". Scale to A4. Move below Background layer.
12. Select Background layer.
13. Filters > Map > Bump Map...
14. Click ? and select "Bump map paper". Adjust settings as required.
15. Image > Flatten Image.
16. Save File.

Instead of Solid Noise try...
Filters > Decor > Fog...
Color = Black. Leave opacity at 100%. Press Ok. Adjust opacity in Dockable Layers.

Thanks; these were both super helpful.

Another great opportunity to learn a new skill - creating parchment and vellum.

It's nothing dramatic - just ads for history lectures. I like to pull contemporary images for them, and for pre-modern topics, that's a lot of vellum.