Colour Check the original thread, conserved as it is interesting

[William Overington]

 

 

This graphic, newly made using Affinity Designer, is based as best I remember, on the design of the Colour Check page that I designed in 1977 and which was displayed on page 786 of the Post Office's Viewdata system. I saw it on a Viewdata equipped television set in September 1977. I do not know for how long that page remained on the Viewdata system.

Please note that the design, in the teletext and viewdata format, is using lowercase letters e in graphics mode in seven colours. The design included eight different control codes, each a number of times. These eight control codes were the Hold Graphics control character and seven control codes of the form Graphics Colour, where Colour can be any one of Red, Green, Yellow, Blue, Magenta, Cyan, White.

Although designed to look as if three semi-filled rectangles, red, green, blue are overlapping, the design needed to have each of the areas encoded directly in the appropriate colour.

William

 

[Alfred]

The white and yellow rectangles seem to have magenta or red edges. Is that intentional?

[William Overington]

6 minutes ago, Alfred said:

The white and yellow rectangles seem to have magenta or red edges. Is that intentional?

No.

The .afdesign file has no such problem.

I have just looked at it at four times magnification and it is fine.

I started off with a canvas 2171 pixels by 1571 pixels at 300 dots per inch, so that I can send a jpg file for a print as a greetings card that I can then frame.

The image that I exported for this thread is a png at 724 pixels by 524 pixels.

I always have a look at a graphic in Microsoft Paint before I upload it to this forum. It looked fine.

However, now that you have mentioned an issue I have, in Microsoft Paint, zoomed in on the png image and I notice a problem that may well be the same as that which you noticed.

So this needs investigating to try to find out what has happened.

William

 

 

[William Overington]

The display in the first post of this thread looks fine to me using this computer with its 13 inch diagonal screen size.

Yet there is something detectable in the image that I uploaded, so it does not seem to be anything introduced by the forum software system.

What is the display that you are using please?

William

 

[William Overington]

I just made a blank canvas 2172 by 1572 and then did a copy and paste, in case it was a rounding error as 2171 is not exactly three times 724.

The effect is still there.

I wonder if a jpg would be better.

William

 

[William Overington]

Here is a full-size png version. It is fine in Paint even when zoomed in.

I expect that the forum software will retrict its size.

How does this look?

 

 

 

 

William

 

[William Overington]

I got back a copy from the forum and it seems good enlarged in Paint.

So I will try to rename this thread and start a new thread with that image. 

William

 

[Alfred]

1 hour ago, William Overington said:

What is the display that you are using please?

I’m using an iPad with a 9.7″ screen, display resolution 2048 px × 1536 px.

 

43 minutes ago, William Overington said:

Here is a full-size png version. 

…

How does this look?

That looks fine. (JPG is generally not a good choice for something like this, since you get noticeable compression artefacts where there is a sharp transition between colours.)
 

1 hour ago, William Overington said:

Although designed to look as if three semi-filled rectangles, red, green, blue are overlapping, the design needed to have each of the areas encoded directly in the appropriate colour.

When you recreated it in Affinity Designer, did you use layer blend modes or did you draw the different coloured areas separately? 

[William Overington]

4 minutes ago, Alfred said:

I’m using an iPad with a 9.7″ screen, display resolution 2048 px × 1536 px.

 

That looks fine.
 

When you recreated it in Affinity Designer, did you use layer blend modes or did you draw the different coloured areas separately? 

I had not heard of layer blend modes until reading your post.

Bearing in mind that I was needing to design as I went along, I started with a rectangle 24 pixels wide by 40 pixels high.

Then I copied it and made the copy 20 pixels high and positioned it so as to give the basic graphic shape correspondimg to a teletext lowercase e.

Then I grouped the two and by using copy and paste I gradually produced the design.

Basically the hypothetical blocks of red, green and blue that hypothetically overlap are each twenty cells wide by ten cells high, so forty chunks wide by thirty chunks high.

If I were starting it again now I would do it differently. I would draw a diagram in pen upon paper, divide it into rectangles, work out where the upper left corner of each rectangle is located, then make the blocks separately, then move them all to the desired positions.

But having got quite a way into it I just continued rather than start again.

I wonder if the original Viewdata page is archived somewhere.

William

 

[Alfred]

11 minutes ago, William Overington said:

I had not heard of layer blend modes until reading your post.

Select either of the upper two groups (i.e. green or blue) in the attached file and inspect its Blend Mode setting via the Layers panel.

The default Blend Mode for a group (e.g. the red group in my file) is ‘Passthrough’ but it’s sometimes helpful or necessary to set it to ‘Normal’ instead.

Viewdata.afdesign

[William Overington]

21 minutes ago, Alfred said:

 (JPG is generally not a good choice for something like this, since you get noticeable compression artefacts where there is a sharp transition between colours.)
 

Does that apply even when using a best quality jpg file, that is, when Quality is set to 100 when exporting a jpg file from Affinity Designer?

The thing is I need to upload a jpg file to the Papier website in order to get a print of a custom greetings card to frame.

William

 

[Alfred]

6 minutes ago, William Overington said:

Does that apply even when using a best quality jpg file, that is, when Quality is set to 100 when exporting a jpg file from Affinity Designer?

Maximum quality corresponds to minimum compression, so it should be OK (especially in a case like this where all the edges are horizontal or vertical, which means there won’t be any antialiasing). Try exporting at various quality settings and comparing the results in AD or your favourite image viewer.