Pixels/gram just for fun

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<p>This is not meant to have any real meaning, I was just ideally thinking about how many pixels I could store with different technologies.</p>

<p>These numbers are only ballpark so don’t worry too much about the details.</p>

 

 

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<p>First up is a 4x6 inch print, figure 300ppi and we get 2,160,000 pixels, weight of a 4x6 inch print is around 3.4 grams, so the pixels / gram works out to around 0.64 Mega Pixels/gram.</p>

<p>A mounted slide weighs in at 1.7 grams and holds between 10-20 Mega pixels, or between 5.9 to 11.8 Mega pixels/inch.<br>

<br />Next I looked at a small drive I have, 325 GB and a weight of 177 grams. Figure 2 pixels/byte and we have around 3,700 Mega Pixels/gram.</p>

<p>My 1.5 TB drive came out close at 3,000 pixels/gram.</p>

<p>The surprise to me was the SD card, weighting only 1.9 grams and holding 4 GB it came out on top, storing 4,210 Mega pixels/gram. And of course 4 GB is not all that large for a SD card, with a 16 GB that would go to over 16,000 mega pixels / gram. </p>

<p>Thinking back to my first hard drive, it weight around 2000 grams and held 20 MB, which works out to around 0.02 Mega pixels/gram, far worse then a print.</p>

<p>A 1.44 MB floppy weighs in at 16.5 grams for around 0.17 Mega pixels/gram, better then my first hard drive, but still not as good as a print. However it is hard to get a print that really shows 300 ppi and jpeg images can be compressed to less then 0.5 bytes/pixel, so in the end a floppy and print come out very close in terms of pixels/gram.</p>

<p>If you are someone who feels the need to store photos as 16 bit/color tiffs the hard drive drops to 306 Mega pixels/gram.</p>

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<p>I have got to ask....did you just retire? :o)</p>

<p>Jason</p>

That's why I print at 200 pixels per inch not at 300 pixels per inch. If I have a whole stack of 8x10s printed at 300 PPI they weigh a lot more than if they were printed at 200 PPI (neglecting the weight of paper). That extra 4,000,000 pixels per print can add up fast.

<p>There's a slight catch: one pixel is actually 3 bytes. So your calculations are too high by a factor of 6. But then of course, one must take compression into account, which can be anywhere from 1:4 to 1:16 depending on quality.</p>

<p>For a 16-bit Tiff, one pixel is 6 bytes (8 bytes if there is an alpha channel).</p>