Changing black tones to white and vice-versa

[nunogarcia]

Hello. This is my first post on this forum, although I've been using Paint.NET for a few years now. I sometimes (many times) have doubts, but I get answers pretty quickly by searching the forum or google. I've been searching for this particular doubt for a while, and I did search in many places with different keywords - however, I'm not a native english speaker, so I might be missing out something real simple.

I'll try to explain what I want to achieve in a few different manners, in hope I'm clear enough to get an answer, although I'm not sure if what I want is possible.

 

1st attempt:

 

Imagine that you have two colors, red and black, and you want to mix 10 drops of red with 3 drops of black. You get a specific color - a weird dark red. Now imagine I have a image with only that solid color and I want to replace those 3 drops of black with three drops of white. How can I do that?

 

2nd attempt:

 

Normal A4 sheets are white, but I want to print a image (with no white or light colors) on a black sheet of paper. I don't need to use a black cartridge, because the black is already there in the paper sheet. How can I remove the "black tones" in order to get proper colors when printing?

 

 

All this to answer one bottom question, which is also my 3rd attempt on this:

 

3rd attempt:

 

I have access to a modified printer that has white ink on the black ink cartridge; that way, If I write a few words in black and print them out on a black sheet of paper, I'll have a white text. This is very simple if I want only to print text; set font color to black and print, ending with a white text printout. But what if I have a photograph, for example, and I want to print it on a black sheet? If I have a white boat, for example, its' color has to be changed to black. If I want to print a light green, I have to have a dark green on my image. Is there any way to do this?

 

I hope I've been clear enough, I've really looked everywhere for an answer, but I haven't come to it. I don't think it is a common question, but I hope someone here knows how to this. If there is anything I've missed, or any additional info any of you need, just let me know and I'll try to add that as soon as possible.

 

Thanks in advance.

-Nuno

 

[Red ochre]

Hello nunogarcia - welcome to the forum!

I like your idea, however I don't think printers work like that - I could always be wrong though!

I believe printer inks are dyes not pigments, that is they rely on the papers' whiteness to give a colour. Think of stained glass windows - they look great against the bright sky but dark at night. I think you will just end up with a very dark image.

I doubt if it is possible to get an opaque white ink to work with a printer without clogging it. If it has been done then all the coloured inks would also need to contain white too, if printing on black paper.

That said if you still want to invert the HSV 'value' of an image it can be done - not sure if there is a plugin for this already (look in the plugin index) - if not I have a half finished plugin that can invert Value.
It can probably be done using the built-in tools 'curves' and 'invert colors' too.

[nunogarcia]

Hi Red ochre! Thanks for your fast reply.

 

I agree with you, dyes rely on papers' whiteness to make a colour. I also agree that printers use dye based inks - but not all of them!

The printer I'm talking about is an Epson. Many Epson printers use pigment ink (they even have a Durabrite logo when they're pigment based, and the one I'm referring uses them. Pigment prints last way more than dye ones - 300 years if kept under museum conditions, about 75 if kept in a frame. Also, pigment inks sit on top of paper, instead of blending in with it. There are also A3 and bigger Epson printers that use light color cartridges like Light Black, Light Light Black and White, all pigment, so I don't think I'll have clogging issues.

 

I made this question because t-shirts, for example, can be printed directly onto fabric using pigment inks - that includes white too. Hence I was thinking, could I print on black paper using pigment ink.

 

That's why I was curious on how to do it (if possible) on Paint.NET. This modded printer has a black cartridge that I might refill with white, but I don't really want to do it not knowing if I can edit images to print them in black pages.

 

I ran a quick search on HSV value, but I don't understand it well enough at this point. I got some part of it, but I'm still trying to figure out how to select only these 'tones', so to say. I'll have to do more research on it before I take any actions.

 

Again, thanks Red ochre.

Cheers.

-Nuno

[Red ochre]

Hi Nuno,

I am still amazed if Epson can effectively print white on black - my reasoning is that even using the highest quality opaque white paint, it takes a thick layer to fully 'cover' over a black background (painting not printing). Still I know printing technology is getting very clever these days - perhaps it works like 3D printing building up layers?

I would think the printer drivers and software for such a machine would automatically work out the correct values for you?

If not, then try to find out exactly what conversions are required and post back. Then hopefully we can work out a method or create a plugin to help. Have you looked up the printer on the Epson site? - perhaps they provide the software or some details there?

Cheers - Red ochre

[nunogarcia]

Hey Red ochre,

Sorry to only reply now, but I was away for a few days.

 

I think we can say it's like a 3D printer, as it prints a layer of ink (and using RIP (raster image processing) software, it is possible to do multiple layers of one color, although in Epson printers, the 'Vivid' quality uses a lot of ink to achieve a solid layer).

 

Epson won't provide details or software for this as this is a modified printer - only Black, Cyan, Light Cyan, Magenta, Light Magenta and yellow cartridges are supposed to fit in there. I've read about using white ink on the light colors cartridges' and being able to print in white. I'm going to buy a used printer in the next few days and when I can, I'll try to do that.

 

Still, I'm having no luck with Paint.NET. I've fiddled around the HSV values, but I can't achieve the colour inversion I talked about earlier - I haven't given up though.

I'll reply as soon as I have news.

 

Cheers,

Nuno

[pdnnoob]

There's a plugin in Ed Harvey's plugin pack called "Invert Intensity."