Quicker way to clean an image

[ineuw]

Among thousands of old images I cleaned up using Irfanview, the attached image is a challenging grayscale 1878 map image and I was wondering if there is a way to clean up the light gray pixels 'en masse', quadrant by quadrant, rather than pixel by pixel. Attached are 2 files, #1 is the original, and #4 is as far as I got. Areas which should be clear white (oceans) are randomly populated by light gray pixels. Whatever I cleaned so far, was done by the Fill paint tool. The question is can it be done by Irfanview, and how? as I want to learn doing it by myself. If it cannot be done, is there a recommended software (a dangerous question) ? Many thanks.

[jazzman]

The problem seems to be that there are bits of the grid that are equal or very close in colour/saturation/brightness to the background, so any "automatic" seems to be decreaseing the image quality.

I did try this:

step 1: increase saturation (eg. IV SHIFT+G and move saturation slider to 200)

This IMO increases the difference between the brown lines and the background

step 2: use a colour replacing tool (eg a filter, there are several to be found on the web)
and replace the yellow/orangy background with white

step 3: reduce to B+W, including increase in contrast, so that gray becomes black

(my result is attached)

There are still bits of the grid that are equal in couour

[ineuw]

Thanks jazzman, your copy is great. I did exactly the opposite and kept messing it up. Since I am new, can you point me to filters. Or, are there any in Irfanview? Thanks again.

[Mij]

The Fine threshold 8bf filter that can be used in Irfanview is quite good for this sort of work.

I used 2 passes of the filter to get this result, setting the threshold just to the right of the main peak on the first pass, then towards the left of the other peak on the second pass.

[jazzman]

Good one Mij - I've got that filter sitting somewhere to, I think. - So hard to remember them all

For colour replacement there is for example Martin Vicanek's free Color Replacer (http://www.vicanek.de/plugins.htm) and some other useful filters. All for free.

[Mij]

Yes that works well too, jazzman.
I had tried the Irfanpaint color replacer which is good for the tricky jobs because you can "paint" over a small area at a time. I found that the tolerance control had to be kept quite low to avoid losing parts of the black and red lines though, so I had to take quite a few samples of the color at different spots to complete the job.

The Martin Vicanek filter seems to have no such problem differentiating between the color that you are trying to replace and what you want to keep over the whole image area.

[ineuw]

I am trying to install the .8bf filters but I don't see them listed in the effects. I placed them in the \plugins forlder. Must I have Photoshop to use them in Irfanview? Thanks in adavance.

[Mij]

No you don't need Photoshop.
Look in the folder that contains i_view32.exe (probably C:\Program files\irfanview). If you have installed the plug-ins pack then you should find a folder there called Plugins. In the Plugins folder check that you have a file called 8BF_filters.dll
In Plugins you will find another folder called Adobe 8BF that may already contain a couple of filters called HarrysFilters.8bf and PopArt.8bf Unzip the 8bf filters that you have downloaded and put them in that folder with any already there.
Now open Irfanview and load an image and you should be able to open a dialog at Image > Effects > Adobe 8bf filters (or press shortcut Ctrl+K).
Click on Add 8bf filters in the dialog box and browse to that Adobe 8BF folder that you put them in and press OK. You should now see them listed in the dialog and you can select the one you want to Start it.
Niggle 1 is that it adds all the filters from the folder even if they are already in the dialog, but do not bother too much about that for now.
Niggle 2 is that all the Martin Vicanek filters open half off-screen but you can click on any of the "brushed aluminium" bits of the dialog box and drag it over.

There is a thread about 8bf filters on the forum.

[ineuw]

Mij, and everyone else who guided me on this post, please accept my gratitude. The results are incredible. You got me hooked. Biblically speaking, since I have no money and my daughters have been married off, each of you get 10 goats or 5 sheep, or, a cup of cappuccino. Take your pick. My thanks to all.

[jazzman]

... In Plugins you will find another folder called Adobe 8BF that may already contain ...

You don't have to put the filters in this particular folder. You can (and should) keep them organized in separate folders (e.g. all filters by Martin V. in one folder, all filters by XERO in another and so on) and then add each folder to the Irfanview filter dialog in the way Mij has described.

[ineuw]

You don't have to put the filters in this particular folder. You can (and should) keep them organized in separate folders (e.g. all filters by Martin V. in one folder, all filters by XERO in another and so on) and then add each folder to the Irfanview filter dialog in the way Mij has described.

I understand and agree. So far, in addition to the IV plugin pack, I only have 2 filters (recommended above), to fix the grasycale images, of which I have thousands. But, as I slowly get up to speed, the plugins will be properly organized. It's the beginning, there is a lot to learn and I am very interested. I proofread on Wikisource, a sister project of Wikipedia, which preserves old documents. I upload the cleaned images to the Wikimedia commons here. http://commons.wikimedia.org/wiki/Ca..._illustrations. Scroll down to see the links to the galleries.

[jazzman]

Just being curious: why don't you keep the colours? The original seems perfectly fine to me.

[ineuw]

It's not possible, although I wanted it at the beginning but the overall results were terrible. The background of the final pages where the images are inserted is white and there was a universal opposition to the yellow, brown colors. Each page, article and volume is a different shade ranging from near white through orange, to the majority being s**t brown.

The originals come from Internet Archives http://www.archive.org/stream/popula.../n301/mode/1up. where it is hand scanned by volunteers. The map appears on page # n301 of Volume 16. Starting from there, the .djvu is uploaded to Wikipedia Commons and transcluded to Wikisource for proofreading here: http://en.wikisource.org/wiki/Page:P...me_16.djvu/306, and finally displayed here: http://en.wikisource.org/wiki/Popula...eather-Service.

For technical reasons, the image is split to two halves by someone before I started to proofread the project.

P.S: The Wikisource .djvu "Index" page of the volume is here: http://en.wikisource.org/wiki/Index:...Volume_16.djvu. There is a dual page numbering system and the actual #306 is different from the numbers appearing. This is marked as [Img] and would be 288 on the page map.