A simple way to re-size pdf files when you don't know the original scale.

MikeBer

Active Member
I have been resizing Zio Prudenzio’s models to 1/32 scale and have found the following the easiest method for me.
I’ve noticed that when the original files are opened in Foxit reader (the simplest to use free pdf reader that I’ve found), they vary in print size when set to 100% zoom.
Using GIMP, PAINT.NET and MS WORD, I can re-size the parts at 600dpi, to any scale that I want and print them on A4 sheets at 100%.
If you don’t already have them, download GIMP and PAINT.NET. (You do not need to know how to use GIMP but PAINT.Net is easy to learn if you have used MSPAINT before.).

PLEASE NOTE!
After publishing this article, I received some very helpful advice from Revell-Fan. Instead of using the BMP format in the following article, you can substitute the PNG format wherever it says BMP.
One of the Export screens in GIMP may differ slightly but Export anyway using the default options.


Download the relevant model pdf file/files and save in your Downloads folder.

pic 01.jpg

Right click and open the file in GIMP.
You should get the following screen.

pic 1.jpg

Change the resolution to 600 pixels/in and click Import.
If there is more than 1 page, select the page you want to edit.

pic 2.jpg

Select File/Export As…

pic 3.jpg

Change the file extension from pdf to bmp and click Export.

pic 4.jpg

Click Export again.

pic 5.jpg

The file is now saved as a BMP.
Close GIMP and this screen will appear.

pic 6.jpg

Click Discard Changes.

You should now have these files.

pic 7.jpg

Now, open PAINT.NET.
It will open on a blank page.

Select Image/Canvas size and then select pixels/inch in the resolution box and change the value to 600.Select the Print size boxes, select centimeters and change the Width to 19 and Height to 28. (The Resolution will automatically convert to 236.22 pixels/cm)

pic 8.jpg

pic 9.jpg

Press OK and save this picture as “A4 Portrait 600dpi.bmp”.

You now have these 3 files.

pic 10.jpg

This will now be your template for saving your newly sized parts at whatever scale you wish.
In the following example, I will convert the Nieuport pdf to 1/32 scale.
Once saved in this scale, if you want 1/48 or 1/72, you can simply change the scale when you print your pdf’s by printing at the relevant percentage.
This will enable anyone who wants to model in 1/48 scale to print the pdf at 66%, and if they want 1/72 scale, then print at 44%.

Now search Google for Nieuport wingspan.

pic 11.jpg
This returned a wingspan of 8200mm

Now, open up the Nieuport BMP file in PAINT.NET and measure the wingspan. In this case it is approximately 117mm.

Here is the simple math.

The real plane’s actual wingspan is 8200mm. A = 8200mm.
A ÷ 32 = 256mm (1/32 scale) B = 256mm.
The wingspan on the original BMP from GIMP = 117mm. C = 117mm.
The % decrease or increase of the original BMP = B ÷ C B ÷ C = 2.18
Therefore, percentage increase of 218%
If B ÷ C is less than 1 then the percentage is a decrease (The Se5a worked out to 0.544 therefore the percentage was set to 54%).

Select the whole image (CTL-A) in PAINT.NET and select “Move Selected Pixels”.

pic 12.jpg

Select Image/Resize… and change percentage to 218 and click OK.

pic 13.jpg

The parts on this BMP file are now resized to 1/32nd scale. (Wingspan = 256mm).

pic 13.jpg

The wingspan is now 256mm.

pic 14.jpg

This file is now saved as “Nieuport 1-32 scale.bmp. This is now our master file of parts.
We can now transfer all the parts at 1/32 scale to the template A4 page/s that we created earlier.

Keep this Master file open in PAINT.NET and open the A4 template page that we created earlier and save it as “Nieuport 1-32 scale Page 1.bmp”
(The one original bmp will now become 3 x A4 pages of 1/32 scale parts).

Select and copy the parts, one by one from the original and place them on the new A4 template pages, rearranging them to fit without changing the size of the page. As each page is filled, save it and open up a new template page alongside the others and save it as page 2 etc.

It sounds complicated at first but after a few goes you will realise how easy it is.
When you have all the parts copied to your satisfaction, you will have 3 pages of parts in A4 format at 100% zoom. Don't be afraid to use more pages if you can't fit them to 3 pages.

We now convert the BMP files back into pdf format.
Open each file in GIMP, select Export as…, and change the file extension to pdf and Export.

You can keep the files separate or combine them into one pdf document with a new file name. I used the free Software PDFill.

pic15.jpg

REDUCING THE PDF FILE SIZE.

Open up each pdf in MS WORD and then save it as a pdf with a new file name (you can rename it later). When saved, close the WORD document and do not save the original pdf file. This file can then be deleted from your Downloads.
My combined Nieuport pdf of 5 pages started out as 44.6Mb but after saving it from WORD, it reduced to 1.04Mb.

Hope this is of assistance to anyone who wants to rescale a file and doesn’t know the original scale.
 
Last edited:

Revell-Fan

Co-Administrator
Staff member
Administrator
Moderator
Thank you for the tut. :)

Everyone should have PDFill. :)

You don't necessarily need to switch between programs and can do everything in Gimp (aside from merging the PDFs). ;)

Just a small tip: BMPs produce very big files which may slow down your machine and / or the editing. I found it more practical to use PNG instead. It compresses losslessly and reduces the file size of the PDF. :)
 

MikeBer

Active Member
Thank you for the tut. :)

Everyone should have PDFill. :)

You don't necessarily need to switch between programs and can do everything in Gimp (aside from merging the PDFs). ;)

Just a small tip: BMPs produce very big files which may slow down your machine and / or the editing. I found it more practical to use PNG instead. It compresses losslessly and reduces the file size of the PDF. :)
Thanks, Revell-fan for the great tip. I used bmp's as jpg files re-compress every time you save them. Do png files do this?
I tried png and the difference between saving from GIMP was that the bmp was 64.7 Mb and the png file was 7.34Mb. Great saving!

The reason that I don't use GIMP for everything is that I struggle to understand GIMP whereas PAINT.NET is a simple one step up from MSPAINT with the advantage that it uses layers.
 

Revell-Fan

Co-Administrator
Staff member
Administrator
Moderator
Thanks, Revell-fan for the great tip. I used bmp's as jpg files re-compress every time you save them. Do png files do this?
I tried png and the difference between saving from GIMP was that the bmp was 64.7 Mb and the png file was 7.34Mb. Great saving!
You are welcome! I'll have to refresh my memory but I think it has something to do with how colour data is stored. BMP saves all data per pixel (colour and coordinates) whereas PNG combines those information. If you have a set of ten pixels in a row which are the same colour BMP saves ten times the same information for each pixel, PNG saves something like "create 10 pixels at coordinates x/y in the colour z". The images do not get deteriorated during saving.

The reason that I don't use GIMP for everything is that I struggle to understand GIMP whereas PAINT.NET is a simple one step up from MSPAINT with the advantage that it uses layers.
I see. There's absolutely nothing wrong with that. The result counts, the way to achieve it is just part of the fun. :)
 
Last edited:

MikeBer

Active Member
Thanks, Revell-fan for the great tip. I used bmp's as jpg files re-compress every time you save them. Do png files do this?
I tried png and the difference between saving from GIMP was that the bmp was 64.7 Mb and the png file was 7.34Mb. Great saving!

The reason that I don't use GIMP for everything is that I struggle to understand GIMP whereas PAINT.NET is a simple one step up from MSPAINT with the advantage that it uses layers.
Thanks, Revell-Fan.
I've attached the following to the beginning of the article .....

PLEASE NOTE!
After publishing this article, I received some very helpful advice from Revell-Fan. Instead of using the BMP format in the following article, you can substitute the PNG format wherever it says BMP.
One of the Export screens in GIMP may differ slightly but Export anyway using the default options.
 

Revell-Fan

Co-Administrator
Staff member
Administrator
Moderator
It took me a while to get used to this "export" thing. I really think they should have kept the old "save as" feature. But after a long time I think I understand why they did it. "Save" usually saves a file in the natural file format of the program you are working with which in this case is XCF. :)
 

OldMiner

Well-Known Member
I found a very useful tool and thought it needs to be here. Convert from scale to scale with no math.
If you have a printout that should be on letter paper, it would be 11” long, an A4 page would be 11.69.

So, using this chart, just use the factor shown. No math other than multiplying by the number in the correct square.
For example, a 1:25 part would convert from 1:25 to 1:35 by multiplying by .714.
An a4 page of 1:25 parts would need to be printed at 8.35” long.

9E883710-F7B0-41AB-81C6-28226756FD9C.jpeg
 

spaceagent-9

Right Hand Man and Confidant
Moderator
Thank you, I love these kinds of hacks on things. I admit that I am not very good at math, but I can eyeball stuff well. I would rather have the scales straight tho.
What I have been doing is to pick the biggest piece, then fit it to print page as large as it can be. The pixel count on the print page must stay the same all the way thru.
(Sometimes I have to chop it up but that is the way enlarging parts goes.)
 

Revell-Fan

Co-Administrator
Staff member
Administrator
Moderator
So what would would 1/24th to 1/18th be then? handy chart, but not all of the sizes in all of the colours!? :hammerhead:
1/18 is the equivalent of row 13 on airplanes. It's evil, no-one builds in it. The same reason why Hasbro is shrinking their Star Wars figures all the time. They don't want to save $$$, they protect us from doom by reducing them to 1/19 and below. ... Ah, ok, I just saw that 1/19 is not on the table as well... Erh, nevermind. Carry on please, carry on..!

:animated:
 

Chuffy70

Well-Known Member
1/18 is the equivalent of row 13 on airplanes. It's evil, no-one builds in it. The same reason why Hasbro is shrinking their Star Wars figures all the time. They don't want to save $$$, they protect us from doom by reducing them to 1/19 and below. ... Ah, ok, I just saw that 1/19 is not on the table as well... Erh, nevermind. Carry on please, carry on..!

:animated:
that's a calculation for Google then? or my partner...she's good at maths - That'll be why the new Dark Trooper is soooo small!?
 

Revell-Fan

Co-Administrator
Staff member
Administrator
Moderator
that's a calculation for Google then? or my partner...she's good at maths - That'll be why the new Dark Trooper is soooo small!?
Exactly! The TVC one is too small and the BS one too big for TVC. It's a conspiracy. And don't get me started on the vehicles which are mostly 1/24... :biggrin:
 
Top