Using Photoshop to produce BBC screens

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geraldholdsworth
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Using Photoshop to produce BBC screens

Post by geraldholdsworth » Tue Jan 21, 2020 12:25 pm

I've been wondering if one could use Adobe Photoshop to turn an image (e.g. a photograph) into something heading towards a BBC Micro screen image (obviously, it won't know about the format). So, I had a play.

First thing I did was to change the colours to Indexed, and restrict it to 8 colours (this was a challenge as, initially, I could find no way to specify the number of colours). I then changed the resolution. However, I realised that it was better to change the resolution before I reduced the colours.

It does a pretty decent job, even though I reduced it to 8 colours and 320x256 resolution (allowed it to stretch the image). But, a MODE 2 screen is 160x256 which produces an oblong image (aka portrait)...but might look different if converted to the correct format and displayed on a BBC.

Got no other use for it...it was just curiosity doing the better of me.
Gerald Holdsworth
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geraldholdsworth
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Re: Using Photoshop to produce BBC screens

Post by geraldholdsworth » Tue Jan 21, 2020 2:47 pm

Thought I'd stick up some samples (of course, this is all academic as there is already an excellent tool for doing this job):
Flying Without Wings resized.jpg
The original
Flying Without Wings 8bit.jpg
Flying Without Wings 8bit.jpg (73.86 KiB) Viewed 421 times
Resolution reduced to 320x256 and colours reduced to 8
Flying Without Wings 4 colour.jpg
Flying Without Wings 4 colour.jpg (68.96 KiB) Viewed 421 times
Resolution reduced to 320x256 and colours reduced to 4

It seems to work better with skin tones:
Photoshop Test - Original.jpg
Original
Photoshop Test - 320x256 8colour.jpg
Photoshop Test - 320x256 8colour.jpg (77.14 KiB) Viewed 421 times
Resolution reduced to 320x256 and colours reduced to 8
Photoshop Test - 320x256 4 colour.jpg
Photoshop Test - 320x256 4 colour.jpg (72.15 KiB) Viewed 421 times
Resolution reduced to 320x256 and colours reduced to 4
Gerald Holdsworth
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geraldholdsworth
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Re: Using Photoshop to produce BBC screens

Post by geraldholdsworth » Tue Jan 21, 2020 3:44 pm

And finally, for comparison, using BBC Micro Image Convertor:
Flying Without Wings Mode 1.jpg
Mode 1
Flying Without Wings Mode 2.jpg
Mode 2
ImageConvertorTestMode1.jpg
Mode 1
ImageConvertorTestMode2.jpg
Mode 2

Right, time to stop playing and get on with some proper work! :lol:
Gerald Holdsworth
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roland
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Re: Using Photoshop to produce BBC screens

Post by roland » Wed Jan 22, 2020 10:03 pm

Cute experiment :)

However, if you zoom into 1000% (or so) you can still see that these jpg's have more colours than expected. I think you should save them in a loss-less format like PNG or BMP to get proper results.
FPGAtom: 512 KB RAM, Real Time Clock and 64 colours
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