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M.Chapman

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About M.Chapman

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Alamy

  • Alamy URL
    https://www.alamy.com/contrib-browse.asp?cid={72CEF26C-BD33-43B9-830D-8FE28CE464C7}&name=Mark+Chapman
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    4570
  • Joined Alamy
    12 Jan 2010

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  1. Yes, let's stick to the simple recommendation that images submitted to Alamy must contain 6,000,000 pixels or more. No ambiguity and no aspirin required. Mark
  2. Isn't the decimal system an anthropocentric system? Why would we be counting in decimal if it wasn't for the 10 digits (8 fingers + 2 thumbs) on our hands? If our counting system had evolved around 8 digits (e.g. 6 fingers + 2 thumbs) then base 8 would have been our anthropocentric counting system and would then have aligned conveniently with a binary 2^n based system which arrived many thousands of years later. Or have I misunderstood? Mark
  3. Would life have been simpler if the human race had evolved with 8 digits on their hands and so had developed a base 8 (octal) counting system (instead of base 10) in the first place? Mark
  4. Crikey you're right. Oops - I've spent too long in the computer world. You're right. A megabyte of data is typically* 1,048,676 bytes, whereas a megapixel is 1,000,000 pixels. I'll correct my last post and a much earlier one in this thread. THANKS! *I see even in the computer world there's some variation. On this Wikipedia page https://en.wikipedia.org/wiki/Mega- it states In some fields of computing, mega may sometimes denote 1,048,576 (220) of information units, for example, a megabyte, a megaword, but denotes 1000000 (106) units of other quantities, for example, transfer rates: 1megabit/s = 1000000bit/s. The prefix mebi- has been suggested as a prefix for 220 to avoid ambiguity. Mark
  5. The difference between 6,000,000 and 17MB is only 1% so the chance of <6,000,000 and still >17MB is quite small. 6,000,000 is also easier to remember than 5,941,931 (17MB of data converted into pixels) and easier to mentally calculate with. e.g. 3000 x 2000 = OK, and includes a small safety margin. I wonder if LR/Photoshop's MB value is rounded up or down? A quick test shows it's rounded (up or down) to the nearest 0.1MB. If I create an image of 2963 * 2000, PS reports it as 17.0MB, whereas it's actually 16.954MB. A further quick test shows that the same 2,963 x 2,000 image is (correctly) rejected by the Alamy uploader as being too small (i.e. less than 17MB). NB. I'm not dismissing your defence of the 17MB limit for those who have LR and know what they are doing (indeed I use a value of 17.1MB to allow for rounding errors myself). But for the rest (especially newbies) a 6,000,000 pixel limit is much easier to understand and can be applied in any image editing software. It also makes it easier to crop in PS without needing to use trial and error (it's a shame the crop tool doesn't display the before/after MB value like resize tool does - maybe you know a trick for this). Mark
  6. In PSE (and PS) you can change the units in preferences or by clicking on the little arrow or triangle at the end of the little display box. Mark
  7. On the LR export menu, I set Image format JPG (this will force a 8 bit RGB data) Quality 90 Colour space sRGB (or AdobeRGB if you want , but Alamy will convert to sRGB on receipt) NO watermarking NO Output sharpening Resize (downsize only) if you want to, but make sure your exported image contains at least 6 million pixels Mark
  8. Not everyone uses PS or LR though. But every package I've used allows inspection of the pixel dimensions and they are visible whilst cropping or resizing whereas MB usually isn't. Let's face it, pretty much all the confusion arises because Alamy 17MB uncompressed size limit keeps being confused with the compressed jpg file size in MB. So let's ditch trying to explain MB which is a rather secondary derived quantity from the pixel dimensions, the bit depth and suffers confusion over whether Mega = 1,000,000 or 1,048,576. We don't sell images according to MB and I think Alamy are now in the minority in expressing their upload sizes this way . Here's my suggested text for Alamy to use on their help page, or pin in this forum? (Thanks to Harry Harrison for the table) Change from File size of over 17MB (when uncompressed/open) Your JPEG file is likely to have a compressed size of 3-5MB. Opening a JPEG in an image program such as Adobe Photoshop will show you the uncompressed/open file size. to Image size Alamy accepts images which contain at least 17MB of uncompressed 8 bit image data. As a simplified guide, this requirement can be met by submitting images that contain at least 6,000,000 pixels. The following are examples of the minimum image pixel dimensions that meet this simplified requirement. 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 format images with more than 6,000,000 pixels images are also accepted Mark
  9. But... if resizing in PS in 16 bit mode, the minimum is 34MB (and that's how it appears in PS). Obviously that becomes 17MB when the image is saved as 8 bit for Alamy, but the recommendation is to work in 16 bit mode until the final save to jpg which automatically converts to 8 bit. Personally I think we should advise new users to just ensure images have at least 6,000,000 pixels as this also avoids the potential confusion over whether Mega = 1024 x 1024 or 1,000,000. PS can be set to show the image dimensions in Pixels. Also when using the resize dialogs in PS the target dimensions are entered in pixels (not MP or MB). Obviously LR export is different. Mark
  10. I've had no word from them yet (I claim directly, not via Alamy). Mark
  11. No. I was merely pointing out that 6 million pixels is a simple rule that works for all formats, including 1:1, 3:2, 4:3 and panoramas, wheres 3,000 pixel long side doesn’t. I was also answering your earlier question. "Panoramas = Why would you ever downsize a panoramic image when the whole point is to increase pixels!!!???" Mark
  12. But this is Alamy's entrance exam. 😀 so they leave as 17MB to confuse and exclude those that don't have the expertise. Mark
  13. But that doesn't work for all formats. Simple rule, make sure you have more than 6 million pixels in the image. Also, I sometimes make panoramic crops from 4:3 images, so going "panoramic" isn't always about increasing the number of pixels. Mark
  14. Definitely an old version - I'm running 1.1.7 which only goes red below 17MB. It would also be great if the author of Alamy SizeChecker could produce a version that also showed green for sRGB as there's absolutely no point in submitting AdobeRGB to Alamy because they convert to sRGB on receipt. In fact I would argue it's better to submit sRGB to Alamy so that you can check the colour rendering and histogram in sRGB colour space before submission. Does anyone know how to contact him? (The contact link on his website no longer works - he's retired). Mark
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