Resizing images

[acctingman]

Originally Posted by RickTNRebel

I print the image out, manually cut and paste (to enlarge), add a scale ruler to the image, then I scan the image, sharpen and resize it (using the scale) in the scanner program before I save it...low tech, but it works!

Rick....you're a better man than I....no way I could do all that

[SCEtoAUX]

Microsoft Paint can resize jpegs. Make sure you maintain aspect ratio.
There are free graphics programs that can resize.
GIMP - The GNU Image Manipulation Program
Inkscape. Draw Freely.
Those are two. Do a search for programs compatable with your OS.
I use PaintShop Pro9 with Windows 7. It is not free, but it does a good job. It can even open a pdf file. The problem with PSP9 is that the virtual pdf printer does not show up in the list of printers so you have to make it the default printer when you want to save a graphic as a pdf when using PSP9 then remember to change back to your actual printer when finished.

You can install a virtual pdf printer so when you want to save as a pdf you choose the virtual pdf printer in the drop down menu. It saves the graphic as a pdf instead of giving a hard copy. You can then print the pdf as usual.
CutePDF - Convert to PDF for free, Free PDF Utilities, Save PDF Forms, Edit PDF easily.
PDFCreator - The free PDF Creator and Converter | pdfforge.org
PDF Converter #1 Free PDF Creator; PrimoPDF
pdf 995: create PDF documents easily for free
Those are free pdf converters.

[acctingman]

Thanks Doug!

[photoguy]

Photoshop LE or Elements is my choice for resizing .jpg files. Remember, it is always easier to downsize vs. upsizing them though. .jpg files are rasterized, meaning they are resolution dependant. They are created with a given number of pixels per square inch. When they are downsized, you throw out some of those pixels, but when you upsize, you are spreading the given pixels apart, and the software then aproximates the color to fill in the gaps. If you push it too far, you will start pixelizing the image.

[SCEtoAUX]

Another free program that is useful is PDFTK Builder. You can get it from here:
PDFTK Builder and other PDF Resources

You can use it to split a multipage pdf into individual pdf pages or combine multiple pdf pages into a single pdf. Quite useful in some cases for manipulating pdf pages and making a single pdf after you have finished resizing graphics and saved multiple pages as pdf's.

[acctingman]

Thanks to everyone, especially Doug!

I'm taking my jpegs and converting them to PDF's via Nitro PDF, saving them, then opening the file in Adobe PDF Reader and presto!

Time to build my army of micro tanks!! :p

Happy building all!!

Bruce

[nebeltex]

another FREE program that has not been discussed recently is "image forge". looks like "paint" but with a many more tools (like twisting image by specific %).

[Mirco]

(Sorry for a very long post. Skip to the last paragraph if you don't need all the theory )


Converting JPGs to PDFs to resize them? That's like buying a car in order to get a snack in McDrive instead of simply walking to the other side of the restaurant.

There are two kinds of "resizing":
1) Just printing in different size. That means, for example, you take an image 1000x2000 pixels big and print it at 10x20 cm instead of usual 20x40 (the numbers are just an example). Probably the thing you want.
2) True resizing. That means, for example, you start with an image file 1000x2000 pixels big and end with 500x1000.

PDF is a vector format. It internally contains all dimensions in some true length units (mm, cm, inch etc.), so there is no problem to determine the true size on paper. Everything depends on your viewer program - some don't allow you to set print size at will. Choose viewer that can do it and you're OK.

JPG is a bitmap format. Its only relation between size in pixels and cm/inch/whatever is a number called DPI (dots per inch). This says how many pixels of the image correspond to one inch on paper. This number can be set to any value to fit your needs - so for example, to print a kit in half size, just double the DPI and request full size print.

Most graphic editors (including MS Paint) allow you to set print size. Not that much editors allow to resize the image pixel-wise, but that's rarely needed. Even fewer editors allow you to tinker with DPI manually, or at least look at the value (for example, MS Paint automatically sets it to 96 every time it saves the image). Some editors don't set DPI at all, which means there is no clue of how big the image is supposed to be!

Print size percentage you set in the "Print" or "Print setup" dialog refers to image DPI. If the DPI is set properly in the image file, this percentage is all you need to set (in MS Paint, it is accessible in "Page setup" dialog). If DPI is undefined or incorrect, the image size is unpredictable, usually ridiculously big or small (depends on default behavior of the program you're using).

OK, that was the image DPI. Then there is the printer DPI - that means how many dots it can print on one inch of paper. This value has nothing to do with image size! The only thing you should know is that if your printer's DPI is very low, your images will look pixelated, regardless of how nice they looked on the monitor. For your information, standard DPI for industrial print (e.g. for magazines, pre-printed models - including the Polish ones - etc.) is 300, good needle&ribbon printers make 180, high-quality photographic laser printers can go up to thousands.

And now the trick: when you send an image to a printer, together with some desired print dimensions (absolute or percentage), it will get there unchanged. The printer itself does the interpolation from the original image DPI times your percentage to printer DPI. That means: pixel-wise resizing before print is useless, it just spoils image quality.

Because PDFs use real dimensions and JPGs use pixels and DPI, inserting a JPG into a PDF has the same problems as a standard print: you still have to set the correct scale. If you think you don't have to, it's because the converter program you use figures it out for you, without asking you what the desired size is. Easy, but sometimes completely wrong.

* * *

So, what's the conclusion?

1) You don't need to really resize the image file itself. Just set the right print scale.
2) You'd better get a program which allows you to look at or change image's DPI. My favourite is IrfanView (www.irfanview.com) - it's small, free, simple, runs on any Windows machine, opens almost any file format and gives you full control over the image you're printing (use "Image info" dialog to check/set DPI and "Print" dialog to set the desired percentage or directly size in cm/inch, position and orientation on the page; full preview is shown as well).
3) If the resulting scale is not exactly the one you wanted, the problem is somewhere between your computer, printer and paper. But you know how big image you want, how big it currently is and what was the size you set, so it's a simple math to make up a new percentage which gives you the desired result. If you're too lazy to do it manually (as am I ), here is a ready-made Excel calculator: http://papergallery.mzf.cz/download/ScaleCalc.xls (third tab).