I want to create a mosaic from a set of photos I already have that will give me another photo. So a set of architecture photos that will give me a big photo of it's creator (the architect). The result for me would be a big print, at least one meter (40") across. Ideally, each tile would be discernible, so you could say: that's a bridge.

I thought it would be easy (or easier), but it's not. I'm using MacOSaiX (a program for doing this), but I'm not limited to a Mac, so Windows software is okay too.

The problems that I'm having the larger picture is not as obvious as I'd like it to be, the set of photos has to be quite large, the portrait of the architect has few different colors (skin, hair, shirt and background) and these are usually not present in photos (you don't see green architecture that often :)).

I have thought of going with black and white, or maybe coloring a subset of photos to match individual colors, but this would take lots of time.

Any tips? Is there better program? Any tips to automate some of the subtasks? Other tips?

  • The thing is these types on program need those colors to work with, so if no green exists, then yeah, it'll look funny. I think you have some pretty good solutions yourself. I would try just generating it and then going black and white and seeing if that's any good.
    – Hanna
    Commented Apr 21, 2012 at 17:04
  • I'm not sure how helpful it'll be but try Mazaika from mazaika.com Commented Apr 23, 2012 at 16:16
  • @Prabin: MosaIT does the same thing and is FOSS. Commented Apr 28, 2012 at 0:51

5 Answers 5


Here is a possible solution if you are open to using Photoshop. Assemble the "grid" of architecture photographs first, in any arrangement, and merge them into one layer. Either convert that layer to grayscale or turn down the saturation. Then, take the photo of the architect, paste it into a layer above the first one, and change the blending mode to "overlay". This will recolor the artwork below the photo with the colors of that photo.

To put more emphasis on the background, you can turn down the opacity of the architect's picture. To put more emphasis on the architect, you can duplicate the layer containing his picture, change the blending mode on this new layer to "normal", and adjust the opacity to taste. I hope that you find this helpful!

  • Hmmm, I really like your aproach, since in all the mosaic pictures I have seen, either the main subject is not great or the individual photos are not visible enough.
    – duality_
    Commented Apr 28, 2012 at 16:50
  • You shouldn't be using Photoshop for creating photo mosaics. Here's why: turbomosaic.com/make-photo-mosaic-in-photoshop.html Commented Feb 15, 2017 at 10:41

If I were to want to do this I would do it like so:

  • Start with a very tight grid
  • Overlay small squares on top adjusting each one's hue to match the general color behind it - when done it should look good. If it doesn't look good here either adjust making the grid smaller yet or tweak your colors until it does.
  • Write down a list/array of say A1 to J70 or whatever where A1 is one corner and nX is the opposite corner, next to each write down a value for the boxes hue
  • Go out and locate images that are predominately the hue needed and check off each square as you go.
  • Place the corresponding image in the corresponding section of the grid.

This is going to be a time consuming process especially since you want to print it because J70 is probably not remotely realistic. You're going to probably need a much smaller grid for the 1m output you're looking for and many many more photos to create the effect.


The color issues are challenging, but the scaling issues are tough as well.

Given you know you want to print it at about 40" across (let's say 40"x40" for the sake of discussion), what size (printed) does each individual image of the mosaic need to be in order to be discernable at close range? And what is the desired viewing distance for the entire printed mosaic? This may also influence the size of the individual photos.

Let's say the smallest an image can be while still being discernable at close range is 1"x1". This would mean that a 40"x40" mosaic would only be made of 40 images in each dimension, which means it can only be used to represent an image that is 40x40 pixels, which is a very small number of pixels for any image.

If you make the individual images 1/2"x1/2", you still only have 80x80 images making up the mosaic. To get an idea of whether 80x80 is enough, scale a square digital image down to 80x80 pixels and view it at 100%. I think you will find that is barely enough detail.

If you printed that 80x80 pixel image at 40"x40", how far away would you need to be standing before it is recognizable as the original image? Probably about 80 times the distance you are from your computer screen (where the 80x80 pixel images is probably approximately 1"). If your eyes are 1 foot away from the computer screen, that means you would need to be 80 feet from the printed mosaic to get a similar impression of the image.

But again, at this point, we are talking about individual images that are only 1/2"x1/2". Are these even big enough to be discernible? I'm guessing probably not. So, I have a feeling that a 40" printing simply will not work. Therefore, I recommend working out the scaling issues first.

Experiment with printing an individual image at small sizes to determine what size is discernible up close, and then think about how many tiles of a mosaic would be needed at that size in order to make the composite image recognizable by working with it on your screen to see how many pixels are needed to give it adequate detail. Then multiply the number of pixels by the print size of the mosaic tiles, and you'll know how big your entire print will need to be, and whether the project is even doable. If it is, then at least you have some parameters to work with in whatever mosaic making software you choose.

I hope this helps and that you get it to work out!

BTW-- I have used MacOSaiX and found it worked well, though when I tried to significantly increase the detail of the tiles it became sluggish and ultimately failed. I don't blame it, I was asking it to do a lot, and it is limited by the computer hardware.


You can use TurboMosaic to make such a photo mosaic. It gives you the option to do cell color matching when the smaller photos don't have colors similar to the source photo.

Here's a sample mosaic made using TurboMosaic:

Mosaic made using TurboMosaic

You can get TurboMosaic here: http://www.turbomosaic.com

(disclosure: I work for the company that makes TurboMosaic)


I'm not familiar with MacOSaiX or the options it provides to customize how a mosaic is made. You may want to try a program like AndreaMosaic which has a feature to "cheat" a little bit by allowing you to change the colors of the tiles by a maximum of a certain percent to obtain the best match with the source image.

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