Author/Presenter/Spreadsheet Consultant Accounting Advisors, Inc.
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Spreadsheets and graphs on a desk

Worlds Colliding: Convert a Digital Photo into an Excel Spreadsheet

Aug 2nd 2013
Author/Presenter/Spreadsheet Consultant Accounting Advisors, Inc.
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In an unlikely mash-up, Matt Parker of Think Maths offers a free tool that converts a digital photo of your choice into an Excel spreadsheet. According to the website",digital photographs are actually just spreadsheets. When you take a photo, your camera measures the amount of red, green, and blue light hitting each pixel, ranks them on a scale of 0 to 255, and then records those values as a spreadsheet." Parker's website is able to extract said values from a digital photo, record the numeric values in worksheet cells, and then use Excel's Conditional Formatting feature to recreate the photograph.

If you have Excel 2007 or later, you can try the technique yourself:

Figure 1: Any digital photo can be converted into an Excel spreadsheet.

Note: The resulting spreadsheet is an XLSX file, which can be opened in Excel 2003 and earlier if you have the Office Compatibility Pack installed. Don't bother doing so, as all you'll see is a bunch of numbers – no photograph.  Parker relies on a feature only available in Excel 2007 and later.

At first, your photo will look much like Figure 2, but if you zoom out, you'll be able to see your photo, as shown in Figure 3. There are several ways to zoom an Excel spreadsheet:

  • If you use a mouse with a scroll wheel, hold down the Ctrl key while you spin the scroll wheel.
  • Choose Zoom on the View tab and then specify 10 in the custom field.
  • Use the Zoom Slider in the lower right-hand corner of your screen, as shown in Figure 4. You can toggle the Zoom Slider on or off by first right-clicking on Excel's Status bar at the bottom of the screen.

Figure 2: You'll only see a tiny portion of your photo until you zoom out.

Figure 3: The author's headshot in Excel spreadsheet form.

Figure 4: The Zoom slider appears in the lower right-hand corner of most Excel screens.

Once the numeric data from a digital file has been written to a spreadsheet, recreating the photograph is a simple matter of using Excel's Conditional formatting feature to color the cells. To see how this works:

  • Click on any cell within your photo.
  • Choose Conditional Formatting from the Home tab and then choose Manage Rules.

As shown in Figure 5, you'll see the technique relies on the Graded Color Scale, where numbers between 0 and 255 correspond to specific shades of color. Thus, by writing the numerical data from a digital photograph, Parker is able to reconstruct any digital photo within an Excel spreadsheet. 

Figure 5: A conditional formatting feature in Excel converts numbers between 0 and 255 to shades of color.

Hat tip to Bill Jelen, aka Mr. Excel, for bringing the Think Math website to my attention.

Read more articles by David Ringstrom. 

About the author:

David H. Ringstrom, CPA heads up Accounting Advisors, Inc., an Atlanta-based software and database consulting firm providing training and consulting services nationwide. Contact David at [email protected] or follow him on Twitter. David speaks at conferences about Microsoft Excel, and presents webcasts for several CPE providers, including AccountingWEB partner CPE Link.

Replies (3)

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By L Keith Jordan
Jun 25th 2015 20:11 EDT

Quite interesting. This explains how digitally touching-up a photo really works. Just another specialized backend database with a specialized GUI viewer on the front end.

Thanks for sharing the tip.

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Replying to evenanerd:
By David Ringstrom
Jun 25th 2015 20:11 EDT

Thanks for your feedback! It was a fun article to write.

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By eamiller1023
Dec 19th 2015 02:11 EST

Hey David,

I just found this article and it prompted me to play around with this idea a little bit. I'm sure an actual computer programmer could do this much more gracefully, but I put together a Matlab script/Excel macro that can convert any image file directly into an Excel image (with true color values in each cell, not the three-cell composites). Let me know if you're interested - it's a fun little distraction!

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