Friday, April 20, 2018

Modified Cover Front and Back pics for iami1 blogbook; Size calculations for these pics

My previous version of cover front, spine and back pics had some margin related issues as covered in my post: http://ravisiyer.blogspot.in/2018/04/first-print-of-iami1-blogbook-shows.html.

When I had shown it to the printing shop operator/assistant guy he had said it was OK. He took the individual front cover page, back cover page and spine pics and said that he would do the needful in Corel Draw to get the job done. So I had presumed that he would have handled size and margin issues using compression or something like that and adding some coloured border if needed. I had not bothered about the particular pixel resolution of the pic, except for ensuring that the width to height ratio of the pic was in the width to height ratio of A5 page size (the book page size). I thought that he would use any tools he needs to compress or even expand the pic as required.

But the sample/trial copy cover pics did not reflect much of such work. Maybe he was too busy or he was not so knowledgeable about taking larger pics and compressing them, adding border areas of particular color etc. Anyway I realized that I now have to figure those things out and give him almost ready, if not ready, to print cover pics.

Given below are the steps I went through to calculate and then prepare the new version of the cover page pics.

1) A5 page size and equivalent picture pixel resolution

After some slip-ups, I learned how Microsoft Paint can be used to easily figure out the pixel resolution appropriate for a particular page size (for a default DPI - Dots Per Inch - value). The A5 page size I am using for the iami1 blogbook has a size of 5.80 x 8.30 inches. I could create a new pic or change size of existing pic, with resolution of 5.80 x 8.30 specified in inches in Paint (instead of pixels). The pic would get resized appropriately. I could then change the size option from inches to pixels. It then showed the pixel resolution for the chosen size (5.80 x 8.30 inches) (for a default DPI - Dots Per Inch). I don't think it is necessary for me to get into the DPI matter and just go with the default that Paint uses.

Paint showed a pixel resolution of 696x996 for the 5.80 x 8.30 inches size jpeg/jpg picture.

2) Coloured (colour fill) border and inner pic size calculations

I decided to have a 5% coloured (colour fill) border on four sides of the previous cover front and back page pics. This border would provide room to easily trim the cover page printout to fit the rest of the book without losing text and other graphic content of the cover pics.

A rough 10% reduction (left 5% + right 5%) calculation for the A5 width of 5.8 inches was 5.8 - 0.6 = 5.2 inches.

A similar rough 10% reduction (top 5% + bottom 5%) calculation for the A5 height of 8.3 inches was 8.3 - 0.85 = 7.45 inches.

[I think I should have been more precise in these calculations. I should have used 5.8 - 0.58 = 5.22 inches for width and 8.3 - 0.83 = 7.47 inches. Maybe I will do that in future.]

This 5.2x7.45 inches is the size of the inner pic within the cover front and back pages which would have a coloured (colour fill) border around them. Paint gives corresponding pixel size as 623x893

3) Compression of previous cover pics to inner pic size

Now the next question for me was whether I should re-create from scratch the cover front page and cover back page as this 623x893 pixel resolution pics. I was not prepared to spend so much time on it now (perhaps will do that in some future version of the blogbook, if at all the blogbook gets into such future versions).

Instead I looked at the option of taking the previous version cover front and back page pics and using a pic compression tool to compress them to this 623x893 size. So that's what I did.

The previous cover front page and back page pics had pixel resolution of 1083x1536 and 1084x1536 respectively.

I used http://compressimage.toolur.com/ free web facility to compress cover front page and cover back page pics to 623x893 size. These compressed pics are given below.

[To open pic in higher resolution, right-click on pic followed by open in new tab/window. In new tab/window you may have to click on pic to zoom in.]






I felt that compression has not really (significantly) reduced readability of text in the cover pics and has not introduced any significant distortions. So I think the above compressed pics may be fine to use as inner pic for the cover page pics.

4) Creation of canvas pic for cover front and back pages and insertion of inner pics at proper place within it

Full page pic size is 696x996. Inner pic size is 623x893.

696 - 623 = 73. Half of that is 36.5. So position for centring left edge of inner pic on X axis (width) would be 36.
996 - 893 = 103. Half of that is 51.5. So position for centring top edge of inner pic on Y axis (height) would be 51.

I created a new empty full page canvas pic with size 696x996. I filled the full page canvas pic with a light blue (pastel) colour.

Within that canvas pic I put up a text box with its left edge at 36, 51. This text box would be fully overlaid by the inner pic with the left edge of the inner pic aligning with the left edge of text box. That pic is given below.



5) Insertion of inner cover page pics into canvas

This was a copy-paste operation from one Paint program instance having an inner cover page (front or back) pic open, into another Paint program instance having the canvas pic with text box showing where exactly the inner page pic should be pasted. Mouse move of to-be-pasted pic followed by keyboard cursor arrow keys helped to position it precisely. The pics produced with this procedure are given below:



6) Filler Spine size calculations and pic

I felt that while a spine with a printed caption on it was not necessary a filler spine with same colour fill as the border colour fill of the front and back cover pages would be appropriate to use.

The blogbook thickness is around quarter inch. So the Filler Spine pic should be 0.25x8.3 inch.

0.25x8.3 inch is converted by Paint to 30x995 pixels.

Expanded that to 30x996 pixels which converts to 0.25x8.3 inch. 30x996 is the appropriate resolution to use.

Given below is the filler spine pic rotated by 90 degrees to be horizontal (to save space on this blog post)


7) Full Cover Pic with front page, spine filler and back page

The full cover with front page, back page and spine filler will be printed in colour on thick and glossy paper (don't know if the Puttaparthi printer will give me Matte and any other options for my small order). I guess that the order and orientation of the combination of pics will be as follows:

a) Back cover page pic followed by Spine Filler followed by Front cover page pic.

b) This pic should be printed in Landscape orientation mode. [OR the pic should be rotated to the right by 90 degrees and then printed in Portrait mode.]

The inner content book will be placed on the middle of non printed side of this full cover colour printout (long and thick paper) with front cover and back cover pages part of the full cover folded around the inner content and pasted/glued to spine part of inner content.

The Full Cover pic resolution width will be 696+30+696 = 1422 pixels. And height will be the same 996 pixels. So resolution will be 1422x996.

In inches it should be width: 5.8+0.25+5.8 = 11.85 inches. And height will be the same 8.3 inches
So inches resolution is 11.85x8.3.

Given below is the full cover pic done by first opening a copy of back page with border pic and increasing its size to above specifications. In the blank area, the front page with border pic and then the filler spine pic were copy-pasted.


I have also given below a rotated by 90 degrees version of above pic.



8) Printing of full cover pic could be done via Paint or Corel Draw or similar program

To print the pic on thick and glossy paper, I think it may be as straightforward as opening the pic in Paint or Corel Draw or similar program, setting page margins to zero, choosing fit picture to page/frame option (so appropriate minor expansion/compression is done), choosing Landscape (or leave it as default Portrait if the rotated pic is used), and issuing the Print command. I tried it with Paint by printing the 90 degree rotated pic file (don't recall which page size I used - maybe it was A4 or Letter size), to a PDF file (instead of a printer) and it came out well. There was just a slight edge of white (on one side only in this case) which would happen with a real printer too and which would need to be trimmed.

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