Wall Graphics

October 15, 2006 8:33 PM

Converting an image to a simple dot-matrix pattern?

A section of my wall is concrete and so I can't hang anything on it. I am planning on buying a few thousand color labels and creating an image in a dot-matrix style. This is a bad example
but kind of along the lines of what I'm thinking of doing, except with an image. Is there a program or application that I can download to convert an image to a dot matrix grid. Basically what I'll do is set up a grid in Illustrator to plan it out, and either there'll be a sticker there, or there won't.

To focus the answers a bit, this isn't a job for Rasterbator or photoshop halftone filter, it needs to be gridded with an "either there's a dot there or there isn't process." Thanks.

posted by Sreiny to computers & internet (15 comments total)

Well, just convert it to a bitmap image in photoshop, that's how I did this image.
posted by delmoi at 8:46 PM on October 15, 2006

What delmoi said. You do have to convert to Grayscale first, because Photoshop won't let you go straight to Bitmap.

Also, you can play with the pixel aspect ratio, under Image, if your labels aren't square.
posted by smackfu at 8:47 PM on October 15, 2006

Crosstitch image conversion might work. One source.
posted by Fins at 8:48 PM on October 15, 2006

I would just resize the image so the dimensions in pixels is the same as the dimensions you want in your color labels. Then reduce the palette to just the colors that you have labels for. The image is then essentially just a matrix of colored points. Zoom in and turn on pixel gridlines if it helps, then replicate on your wall!
posted by stopgap at 8:48 PM on October 15, 2006

Stopgap has the right idea, but I'd reduce the palette first, it will give you better results.
posted by aspo at 9:03 PM on October 15, 2006

This probably isn't quite exactly what you are aiming for (because it does ascii, not dots) but perhaps with some tweaking it could do the job.
posted by brain cloud at 9:04 PM on October 15, 2006

The Rasterbator
posted by stavrosthewonderchicken at 9:09 PM on October 15, 2006

- establish a grid unit size (let's say 2"x2" as an example)
- establsih your overall image size (let's say 4'x4')
- that means you have a 24x24 grid
- in Photoshop, convert your image size to 24 x 24 pixels
- convert to greyscale
- covert to bitmap: conversion method here will determine the overall look of your image. Diffusion will give a dotted stippled look, 50% threshold will give you a stark black and white. Custom patten can do interesting things (try a small black to white vertical or horizontal gradient as a pattern). Pushing the values around with levels or curves can give you more control in this step.
- Now you probably have a smaller image that you want. Go to Image Size, set the overall size value you want. Set the Resample mode to Nearest Neighbor. Resize.
- Bring this into Illustrator, lay down your grid lines on top.
posted by doctor_negative at 5:50 AM on October 16, 2006

I suppose these are things I should know, but aspo, could you explain how to reduce the palette first? Does that just mean reducing the image to 2 color? Thanks.
posted by Sreiny at 5:54 AM on October 16, 2006

I suppose these are things I should know, but aspo, could you explain how to reduce the palette first? Does that just mean reducing the image to 2 color? Thanks.

Image/Adjustments/Posterize. You can select the number of colors.

If you're going for more than 2 colors, then the bitmap conversion won't work. But if you replace the bitmap step with posterize and you can still basically follow the steps. The problem with posterize is that has no application method choice. If you instead, convert it to Indexed Color, you can pick the number of colors and the application method.
posted by doctor_negative at 10:25 AM on October 16, 2006

OK, this is ultra geeky but you could also convert each channel to bitmap separately and then recombine them in in a new RGB file.
posted by doctor_negative at 10:29 AM on October 16, 2006

You want the rasterbator, linked above.
posted by hatsix at 7:51 PM on October 17, 2006

I should expound, since you said "no rasterbator"... you want to reduce colors using posterize THEN convert to indexed colors, then Rasterbator
posted by hatsix at 8:02 PM on October 17, 2006

Sorry, I missed the 'no rasterbator' bit above.
posted by stavrosthewonderchicken at 11:22 PM on October 17, 2006

I agree with doctor_negative on this one, use a grid the size/ratio of your wall.

Once you've established that, establish a formula for each "dot".

i.e. if the square here has a brightness above 50%, then its a dot.

A more complex, but similar system can be found here. You can even use it as motivation / brainstorming.

Good luck, and maybe post a pic when you're done.
posted by psyward at 4:43 AM on October 20, 2006