Harry Harrison

I'm getting there but I'm still attached to 30 psi, must learn to go for 2.1 Bar instead. Heard a radio talk show host berating a caller for expressing distance in kilometers. Oh well.

Who knows, we might be going back to them here soon......

Well, whatever....I still think your proposed 6,000,000 pixel (6 MP) rule has a nice ring to it!

I'm getting confused now, surely 6 MP is 6,000,000 pixels, that's certainly what camera manufacturers use? 6MB is 6,291,456 bytes.

Thanks, not a make I was familliar with but I get the idea.

By the way, at the moment it's 17MB, or 5941931 pixels, the consensus is that 6,000,000 might be easier to remember!

Thanks for that, sounds like the experience made a huge impression, on you as well as the sensor!

Interesting, do you mean a desktop lab vacuum pump, or simply a household vacuum cleaner with HEPA filters? Those desktop lab pumps seems to be very pricey.

Crikey, do you mind saying what happened? I haven't had to do a wet clean but I'm led to believe that the 'glass' over the sensor is pretty tough.

My pleasure, I can't resist a nice little spreadsheet! Yes, the panoramics were just for illustration, they can of course be any aspect ratio over 2:1 as MDM says so they don't fit into a table format well. I also probably wouldn't recommend the more extreme crops, they must surely have limited usefulness at that resolution even if technically they should pass QC. Also of course anyone is at liberty to crop their pictures in any direction without it being for a panoramic so they will still need to be able to work out the size. I think the simplified table would be very useful on the appropriate Alamy page and should at least stop new contributors going down any blind alleys in terms of misunderstanding jpeg size.

As a postscript to this thread here are two tables showing the minimum pixel dimensions permitted for uploading to Alamy for the different formats/aspect ratios: The first is the official Alamy requirement for 17MB uncompressed, the second the suggested 6,000,000 pixel alternative, both very similar in real terms of course. Alamy spec. - 17MB uncompressed Format Aspect ratio Long side Short side Square 1 2438 2438 Micro 4/3 1.33 2811 2114 Full frame/APS-C, 1” 1.5 2985 1990 Panoramic 2:1 2 3447 1724 Panoramic 2.5:1 2.5 3854 1542 Panoramic 3:1 3 4222 1407 Panoramic 3.5:1 3.5 4560 1303 Panoramic 4:1 4 4875 1219 Panoramic 4.5:1 4.5 5171 1149 Panoramic 5:1 5 5451 1090 Alternative – 6,000,000 pixels Format Aspect ratio Long side Short side Square 1 2450 2450 Micro 4/3 1.33 2825 2124 Full frame/APS-C, 1” 1.5 3000 2000 Panoramic 2:1 2 3464 1732 Panoramic 2.5:1 2.5 3873 1549 Panoramic 3:1 3 4243 1414 Panoramic 3.5:1 3.5 4583 1309 Panoramic 4:1 4 4899 1225 Panoramic 4.5:1 4.5 5196 1155 Panoramic 5:1 5 5477 1095

Looks good to me, it means the threshold for uncompressed file size is in effect raised to 17.16MB but that's a small price to pay for the sake of simple maths! Incidentally I'm not sure if Alamy actually define their 'panoramic' filter anywhere but in a cursory search I've found one image at exactly 2:1 Aspect ratio but none below that so I suspect that is the threshold.

Yes, absolutely, and you could add 2:1, 2.5:1, 3:1 panoramics to that I guess, so a chart like this would be a guide and help new contributors understand but ultimately Alamy have got it right by specifying a minimum uncompressed size and getting the photographer to understand the basics.

That's what I was pointing out, a panoramic with a longest side of 3000 pixels would be downsizing, it wouldn't meet the Alamy spec.

Well that sounds OK, the information with the last update in February 2015 said the following, which was clearly based on earlier Alamy standards: Colour codes Size - Red for less than 24MB (Fail), Blue for 24 to 48MB, Green for 48MB and above. I can see that it can be useful and I should probably spend more time looking at it before commenting, it's very quick and you can sort on the uncompressed size column.