I don't really fully understand Dots per Inch (DPI) and printing...the general gist of this post is that all is not lost with a low DPI image, it can be made printworthy! :D Moving on!
|The photo, the touch up and the finished printed box.|
I wanted a miniature Doubl Glo holiday snow box, but the only image I could find of one was on eBay, and it was a photo of the box and the photo was 96DPI. It is recommended to use somewhere between 150 and 300DPI for miniaturizing. Because the Doubl Glo image was fairly simple, I used the paint function in PhotoImpression5 to improve the image for printing. PhotoImpression5 was a free software disc that came with my digital camera, so it's likely many people have something like this lying around.
And to find out what number of DPI your image is, right click on it, select properties from the box that pops up, and you will find the DPI number in there.
Using a flickr image from the lovely Joanne of Takeabreakwithme, I'll roughly explain how I improve those low DPI images for printing in 1:12 scale.
This is a 96DPI image.
Disclaimer.. After reading a few online articles I assume that...
...if I was to print this image as it is on the left, the printer nozzle would attempt to replicate all of those tiny squares of black tones, red tones, etc. as best it could. The printer has a palette of only four "crazy" printer ink colours (black, yellow, magenta and cyan) to work with, carefully arranging many dots to simulate each of those tones, and then.... each ink dot will bleed into the paper, merging slightly with the dot next to it...fuzzy outcome highly likely.
Even just one colour tone needs to be simulated using many dots of ink from the palette of black, yellow, magenta and cyan. By having a uniform red tone, the printed red will be more intense and less fuzzy due to the printer not having to replicate those unnecessary tones.
If you have Arcsoft PhotoImpression or some similar form of photo editing software, open the image and find the paint tools. Click on colour picker, which should look like a little ink dropper. Zoom in on the image and select your favourite tone of red from one of the many pixels to choose from..
Once you have selected your favourite red, click on the bucket of dripping paint, and choose solid fill and have the opacity set somewhat as shown (maybe a bit more in the middle...) and colour in your image. If you find there are pixels that haven't been coloured, use the ink dropper on them, colour the whole area with the new colour, and then turn it back to red (make sure you have an area of red left somewhere before doing this..otherwise just leave the pixels and colour them in manually with the spray paint option)
If you have ever used MsPaint to paint with, you will know that it can paint in quite a disastrous blocky way, as it only enters pixels with the exact same tone of red. The opacity setting in photo editing paint tools helps the red "paint" bleed into all of the red toned pixels, in just a few clicks. You do need to play about with it, and if there is a disaster, ie. something not red, suddenly turns red, there is an undo button.
A 96DPI print result, before and after, would have been good, but unfortunately my printer is still out of order. I used this method on the Christmas box and Firework printables, and they were all lower than 150DPI.