How to covert negative images to positive images

[satimis]

Hi all,

How to covert negative images to positive images

I have posted this question before but I couldn't find a reliable solution.

Running on Terminal

$ convert -negate source.png target.png

But the quality of the positive images converted are poor.

Steps performed by me creating the negative images on films
1. Use a 12" tablet as light box
2. Mount the film on film holder
3. Place the film holder on top of the tablet
4. Take photos with a mobile phone camera mounted on a tripod

I have no problem taking negative images from films but I couldn't find a solution converting the negative images to quality positive images.

Please help or advising me where I should post my problem for a solution?

Thanks in advance

Regards

[ajgreeny]

Are you trying to do this with command line or using a GUI application? I am certain imagemagick can do it but can't give you the command now as I'm on an Android tablet.

Don't forget many if not all GUI image editors, eg gimp, can do the job easily though I can't comment on the quality of the output image.

[satimis]

Are you trying to do this with command line or using a GUI application? I am certain imagemagick can do it but can't give you the command now as I'm on an Android tablet.

Don't forget many if not all GUI image editors, eg gimp, can do the job easily though I can't comment on the quality of the output image.

Hi ajgreeny,

Thanks for your advice. I have tried command line before but the quality of the positive image was not good. I think that this is not the road for me to follow.

Regards

[dragonfly41]

Recently I suggested in another post leveraging Wolfram language.

Same applies to this requirement.

But admittedly Wolfram features can be rather overwhelming.

https://reference.wolfram.com/langua...lorNegate.html

[ajgreeny]

I have just used imagemagick to convert a positive photograph to negative then used nomacs to invert that image back to positive.
All went very well with no real difference between the original and the double converted.

Just to be sure I also did this in both directions, positive to negative then negative to positive 3 times each using the most recently converted image so I ended with 4 versions of each image, positive and negative.
I could detect no difference between the 8 total of images and all exif data was retained etc etc. and the images all appeared visually identical

The command used was very simple

convert positive.jpg -negate negative.jpg

Why not give it a try?

[satimis]

Recently I suggested in another post leveraging Wolfram language.

Same applies to this requirement.

But admittedly Wolfram features can be rather overwhelming.

https://reference.wolfram.com/langua...lorNegate.html

Hi dragonfly41,

Thanks for your advice.

I'm searching for a simple and straightforward solution, if possible. I have hundreds of negatives to develop. I can further treat the developed positives on GIMP or Darktable.

Regards

[dragonfly41]

Intuitively I would use a tool such as Albert, write a Python extension to automate the process. You can then write your own commands in the popup query field. Try the standard plugins.

P.S. Example of custom Albert / Python script here:

https://github.com/albert-ying/ImageTools

Actually the above post is not related to Albert launcher. The developer is named Albert.

Here is another attempt to show examples of plugins. But write your own..

https://github.com/bergercookie/awesome-albert-plugins

[satimis]

I have just used imagemagick to convert a positive photograph to negative then used nomacs to invert that image back to positive.
All went very well with no real difference between the original and the double converted.

Just to be sure I also did this in both directions, positive to negative then negative to positive 3 times each using the most recently converted image so I ended with 4 versions of each image, positive and negative.
I could detect no difference between the 8 total of images and all exif data was retained etc etc. and the images all appeared visually identical

The command used was very simple

convert positive.jpg -negate negative.jpg

Why not give it a try?

Hi ajgreeny,

Thanks for your advice.

I have tried long time ago on Terminal running

$ convert negative.jpg -negate positive.jpg

The quality of the postive.jpg was poor.

I just tried it again, with the same poor positive image resulted. No improvement

Regards

[satimis]

Intuitively I would use a tool such as Albert, write a Python extension to automate the process. You can then write your own commands in the popup query field. Try the standard plugins.

P.S. Example of custom Albert / Python script here:

https://github.com/albert-ying/ImageTools

Actually the above post is not related to Albert launcher. The developer is named Albert.

Here is another attempt to show examples of plugins. But write your own..

https://github.com/bergercookie/awesome-albert-plugins

Hi dragonfly41,

Is it the plugin for GIMP? I haven't added it

Regards

[Dennis N]

In GIMP, it's in the Colors menu.
Open the image file, then
Colors > Invert