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Clyde

1bit / bitmap mode colour format?

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Hello,

I can not find a Bitmap mode in 1-bit Photo Affinity off I need to process files that keeps strictly their mode and their resolution.
This is copydot files and it is important that it be treated as such.

It is provided a 1-bit Mode?

If that were the case , it might be interesting to have a true improvement over Photoshop that generates moiré patterns when you want the resample .

 

 

 

(This messages was à Google Translate).

 

 

 

 

Clyde

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Seems AP cannot handle 1-bit art. I am writing a feature request about it.

 

Meanwhile I guess it is Photoshop or possibly Photoline which can use 1-bit colourspace.

 

Why do you resample copydots? Target device resolution differs from original? I expect there will be problems just like moire.

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Ok here it is as request :-)

 

1-bit bitmaps are used as line art (printed cartoons, illustrations), in silk screen printing and copydot printing systems. They also can (should) be used in coloured comics, where colour plates are overprinted with 1-bit black key colour. Possibly there are other technical purposes also (please list them in this thread!) There is not many apps that support 1-bit but for these uses 1-bit is crucial. 1-bit ensures that black image is NOT rasterized, resulting fuzzy outlines.

 

Technically 1-bit colour space should be easy feat. You can convert greyscale image to 2 tones (b & w) by thresholding image where light areas convert to white and darker to black.

 

Threshold should be adjustable so you can select how black or how white image is. (Scanners can scan directly to 1-bit but I think it is much better scan to greyscale and set the threshold manually.)

 

Alternative to thresholding is dithered image – that is, using something like grain mask or stochastic raster or Atkinson dithering to build the greytones. I am not sure that is so much needed as it is just a special effect (imho). Besides, there is excellent HyperDither app available.

 

There are some angles that are worth considering. Colour images are best at about 300 dpi when printed. 1-bit images display jaggies in that low resolution, optimum res is 1200-2400 dpi. Ideally 1-bit pixels would map 1-1 to device pixels but above 1200 dpi that is academic.

 

Details are not needed in that high resolution range, meaning that true 1 pixel resolution is not needed. Resolution is needed for avoiding jaggies, making lines and shapes smooth and clean. That also means that you can upsample image to smooth jaggies out. It is perfectly ok (even when not really hi-fi) to take 300 dpi greyscale image upsample it to 1200 and convert to 1-bit. In photoshop you can upsample in convert dialog (doing 300>1200 AND 8-bit to 1-bit) but I think Photoshop did it wrong and resulted jaggies. I do not know if they have corrected that bug (I use PS CS5). I hope AP would upsample and convert at one go and do it right.

 

There are some massage you can do to makes 1-bit appearance better. You can play with local contrast to make darker parts lighter so there will be more meaningful black and white areas in image. You can do it manually, or you can use filter (I think high-pass filter is used here?) I am hoping Affinity team would find some quick and easy slider here to apply in convert dialog to reveal more detail in final 1-bit image.

 

Tools: there is not much need for any special tools. (Or is there?) You can paint pixels black or white and that is it.

 

One simple effect/usage mentioned also in Affinity forum is that 1-bit image is placed in page layout app and coloured with front and back colour tools.

 

Last, you might want to consider comix artists' work flow. Old school draw black&white, scan b&w original (1200 dpi) and hand a copy to colour artist for colouring. Colouring is done to separate layer (well, sometimes physical "layer" with brush and paint). Coloured version is set in place in page layout and higher res lineart version is set in register with it and overprinted. Should colour image be CMYK? Or would it better be CMY, resulting brighter colours and less ink coverage, considering there is still black key 1200 dpi image being overprinted? How do you do CMY separation? Also, there are artists that draw with colours so that final artwork is coloured physical art board, and the either take the easy way out and do normal 300 dpi art production, OR filter out the 1200 dpi black key from full colour scanned original (not easy process..). Possibly Affinity can troubleshoot this process to simple and easy colour sep system for comix artists.

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It happens that I work in comics (for an editor).

 
And images "lines" are usually in Tiff 1 bit Bitmap.
These images must retain that resolution and transparency is managed by the postscript fashion "overprint" ... which is much faster and more respectful of the original color that we place below.
 
We also have the problem of the Manga that comes Bitmap Tiff 1 bit and that should not change under penalty method to obtain moiré.
 
Today we are working with Photoshop but I'd like to propose an alternative.

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Clyde: Have you tried Clip Studio Paint EX yet? Specifically designed and developed for comics work, Clip Studio Paint EX might be your (potentially ideal) software: it specifically supports 1bit 1200ppi raster layers and 600ppi (or lower) full colour or greyscale layers. And vector layers as well (which are translated to raster in the final output).

 

Full support for page management, panelling, tones, etc.

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Thank you for the info.

I'll look at this more ready but if I seek an alternative to Photoshop is to find at least the same functions. For me Affinity can not currently replace PSD but be a complement. Clip Paint Studio as elsewhere.

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An earlier Feature Requests thread about 1-bit bitmap mode can be found here.


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We would be interested to know why you use 2 colour formats. Could you achieve a similar result using RGB with a 2 colour format at export time?

For bitmaps, the two colors can be colored as desired or made transparent in InDesign. Very convenient and requires little RAM.

In Photoshop you can convert to Bitmap with 50% threshold (s / w), or with Diffusion Dither (what visually appears like a grayscale image).

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We would be interested to know why you use 2 colour formats. Could you achieve a similar result using RGB with a 2 colour format at export time?

 

If I understand it correctly, this is also desirable in order to prepare images that are to be printed in two spot colours (in offset, letterpress or silkscreen). I might be wrong but I don't think you can use RGB for that.

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Could you achieve a similar result using RGB with a 2 colour format at export time?

Is it possible to convert to 1-bit format at export? I don't think so. If it were possible it would work, as it is possible to make RGB file which has only 2 actual colours. But as I understand in AP the file just stays RGB in export and halftones in print.

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I would expect 1-bit images to be TIF.

 

I would expect TIFF support to include 1-bit (e.g. ITU-T/CCITT Group 4, as commonly used for fax transmission) but I wouldn't expect all 1-bit images to be TIFF.


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Affinity Designer 1.6.5.123 • Affinity Photo 1.6.5.123 • Windows 10 Home (4th gen Core i3 CPU)
Affinity Photo for iPad 1.6.11.85 • Affinity Designer for iPad 1.6.4.45 • iOS 12.2 (iPad Air 2)

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What about adding a Bitmap Live/Filter ?

 

It would have Settings for the type of conversion to bitmap to apply: diffusion dither, stochastic, etc.

 

This is a historical effect from the early days of DTP (I used to be wowed at seeing the laser prints coming out of the LaserWriters) which many find aesthetically beautiful and would love to see preserved in AP...

 

Thanks for your consideration.


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I am afraid filter would not change image format to 1-bit, it would just make normal 8-bit per colour channel to look like 1-bit. Of course if there was true 1-bit export available (I would prefer TIF) it would help.

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I work a lot with calligraphy, which I scan from original on paper. The printers will not accept ANYTHING except pdf in bitmap (1-bit) mode. I really want to use Affinity Photo instead of Photoshop, but this is a very important missing piece for me.

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AP can export to 1-bit gif and png (using black and white preset) though it has no 1-bit work space. How to make a PDF of that is another question. And it should be noted that AP always dithers in export which complicates issue even more. Even if art is prepared to look 1-bit in 8-bit mode I suspect some dithering will stay in borderlines.

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I work in letterpress printing and screenprinting and use 1 bit mode every day. Please include this feature.

 

Reiterating what others have said:

Letterpress require a solid, no line screen image to make clean film for plates. We, too, scan calligraphy for invitations at 1200dpi for high resolution platemaking.
In PS I  scan>convert to greyscale>play with levels, then Threshold>convert to bitmap. Then I colorize with spot (Pantone) colors in layout software.

 

I've been doing this for close to 20 years (yikes) and am happy to consult to bring this feature to Affinity.

thanks!

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1-bit mode would be very welcomed.

 

The only image editor that I am aware of that supports 1bit layers with high PPI resolutions and allows these to be combined with 300ppi colour ones in the same layer stack is PhotoLine.

 

Crossing my fingers for Photo's next version that will hopefully support 1bit properly.

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