Check Your Images at 100%

[suziq]

Hi all

 

This is my first post and I am reasonably new to photography.  I have searched elsewhere but can't find the answer to this question.  What exactly does "Check your images at 100%
All images should be checked at 100% (actual pixels) for correct exposure, colour cast, noise, camera shake and that no sharpening has been applied etc. using professional imaging software." mean and how do I do it?

Apologies if this has been addressed somewhere else or if it's a really dumb question!

 

Thanks

Suzi

[sb photos]

10 minutes ago, M.Chapman said:

 

100%? If so this could be a key reason why the number of QC fails reported on the forum seems to have dropped in recent times?

 

Mark

 

When viewing at 200% on  a MBPr 13" the image starts to pixelate.

[Harry Harrison]

9 hours ago, MDM said:

I don't think there is any advantage for stills photography at 27" or less

 

Thanks, I suspected as much, but I suppose for those upgrading in the Apple universe there is no choice.

 

11 hours ago, sb photos said:

I often wonder what what displays are currently used by picture desks and Alamy for QC?

 

Good point.

[MDM]

46 minutes ago, Harry Harrison said:

 

Thanks, I suspected as much, but I suppose for those upgrading in the Apple universe there is no choice.

 

 

Good point.

 

Yes there is - use an external monitor as well if buying an iMac but iMacs are relatively limited in terms of upgrading. Or buy a MacPro - very expensive though. Apple have tended to neglect this market but have announced a new even more expensive one coming this autumn. With the continually plummeting £, the final cost is anyone's guess.

 

Right now following the latest developments: £1 = $1.22, €1.09

[Harry Harrison]

29 minutes ago, MDM said:

but iMacs are relatively limited in terms of upgrading

 

I'm psychologically preparing myself to replace the defunct hard drive in my old Imac, what a performance. Still I have to say that it's very nice when it's working though I don't use it for PP.

[geogphotos]

13 hours ago, M.Chapman said:

Hi Ian,

 

A typical (standard resolution) display has around 100 pixels per inch (PPI)

The latest 4K, 5K and retina displays can have pixels that less than half the size at 200 PPI or higher

 

If, for example, a 1000 x 1000 pixel image is displayed at 100% (i.e. each pixel in the image is displayed using single pixels in the display) on a standard display it will be 10" x 10" on screen.

But, if the same image is displayed on a retina display at 100% it will only be 5" x 5". If the viewing distance isn't reduced (to take a "closer look" at the smaller image) the 5 x 5 inch version will appear 2x smaller and hence 2x sharper. You may also not be able to see single pixel defects in the image (CA fringe, dust etc.) as they appear 1/2 the size.

 

However, if the image is displayed at 200% on a retina display it returns to the same size it was displayed on the standard resolution screen. Alternatively the image can be inspected from half the distance, but that may lead to bad posture, neck and back ache!

 

Hope that helps.

 

Mark

 

Thanks very much Mark. I would assume that a lot of people in the world of stock photography use Macs and this sort of display. It does make me wonder if those doing QC at Alamy and elsewhere are viewing at 100% rather than 200%. 

 

Thinking back to viewing slide scans at 100% and contrasting that with now and using 27inch Retina it makes it clear to me that judging sharpness of focus, noise etc is quite a subjective business.

[MDM]

15 minutes ago, Harry Harrison said:

 

I'm psychologically preparing myself to replace the defunct hard drive in my old Imac, what a performance. Still I have to say that it's very nice when it's working though I don't use it for PP.

 

External solid state drives running through USB3 connectors on the computer or Thunderbolt drives (desktop or mobile) can be extremely fast, negating the need to replace the internal drive but  will depend on the age of the machine as to their usability. In recent years Apple seem to have been moving towards making their machines not upgradeable which is a real shame.

[M.Chapman]

2 hours ago, geogphotos said:

 

Thanks very much Mark. I would assume that a lot of people in the world of stock photography use Macs and this sort of display. It does make me wonder if those doing QC at Alamy and elsewhere are viewing at 100% rather than 200%. 

 

100%? If so this could be a key reason why the number of QC fails reported on the forum seems to have dropped in recent times?

 

Mark

[sb photos]

2 hours ago, Harry Harrison said:

 

I'm psychologically preparing myself to replace the defunct hard drive in my old Imac, what a performance. Still I have to say that it's very nice when it's working though I don't use it for PP.

 

Harry, It's relatively easy replacing a hard drive or upgrading to an SSD internally in all iMacs, but I've replaced hundreds, working on Mac's since 1987. What iMac do you have?

[sb photos]

9 hours ago, MDM said:

 

I don't think there is any advantage for stills photography at 27" or less as the pixel density is too high for comfortable viewing in my opinion. I guess there are advantages for video makers if they are shooting at those higher resolutions but not something I know anything much about at the moment. My son got one of the first 5K iMacs when they came out and I've had a few plays with it but I would take my 27" Eizo at 2560 pixels any day with or without a second monitor.

 

The main advantage is to the manufacturer not the stills photographer, unless you also shoot 4K video. Like all industries, display manufacturers continuously push new technology to the masses to keep up sales revenue.

 

Personally I undertake photo editing at home on a Mid 2012 15" MacBook Pro (i7 quad core) 1TB SSD 16GB memory and the amazing AG hi-res display (1650 x 1050), but carry smaller and lighter options in my shoulder bag or back pack.

[Harry Harrison]

2 hours ago, sb photos said:

Harry, It's relatively easy replacing a hard drive or upgrading to an SSD internally in all iMacs

 

Thanks Steve, that's very encouraging, I have watched the videos and practiced on our previous 'white' Imac (no longer required) so I can see that it should be within my capabilities and I have the tools though it's a little alarming how much surgery is required to get to it.

 

It's old so not worth going to an SSD really as we only use it for the internet in the kitchen, for which it is ideal. I bought a new 320GB hard drive plus a USB El Capitan boot drive (I just hadn't got around to making my own stupidly). It began dropping out to the '?' over a period of weeks then would only go to that. I can hear the hard drive trying to start a few times then giving up.

 

I do have a question though, if you don't mind. In its present state I can't get it to go to Startup Manager using the Option key on startup so cannot see the USB boot drive, I just get a white screen with the cursor, which I can move. If that still happens once the new drive is in then obviously I'm stuck.  I'm using a relatively old white plastic wired keyboard, not aluminium as I'm pretty sure you can't use the Bluetooth 'Magic' keyboard that we normally use. Any ideas would be gratefully received!

 

Oh, and it's an A1224 so that is pretty old of course, though I'm happy with El Capitan and all the browsers still work, unlike the 10.6 White Imac.

[MDM]

Are you able to run the Apple Hardware Test . Hold down the D key when you start up and see what happens if anything.

[Harry Harrison]

7 minutes ago, MDM said:

Hold down the D key when you start up

 

Thanks, I've just tried that but it seems to ignore what I'm doing on the keyboard and just tries to launch the hard drive then goes to '?'. I had already gone through the reset PRAM procedure though can't be sure it was successful, it beeped several times at least.

 

Could it be that the white Apple keyboard (A1048) doesn't work with it? I'd read that some keyboards don't work.

 

Just going out for a few hours but thanks for your suggestion.

[M.Chapman]

5 hours ago, sb photos said:

 

When viewing at 200% on  a MBPr 13" the image starts to pixelate.

 

Pre-retina display? Viewing rather closeup? Bionic vision? What resolution is the screen on your MBPro 13"?

 

Mark

[sb photos]

10 hours ago, Harry Harrison said:

Oh, and it's an A1224 so that is pretty old of course, though I'm happy with El Capitan and all the browsers still work, unlike the 10.6 White Imac.

 

I know that iMac well, it's easy to work on. The original 320 or 250GB hard drives were very unreliable. When you replace the hard drive the black plastic clip and black foam that attaches the temperature sensor will require fresh double sided tape attaching. I have seen some failed 320GB drives that stopped you booting from an external drive until it was either disconnected or replaced. The keyboard should be OK. If the original drive was simply not seen the iMac should eventually have booted from the next available boot device, ie your installer. The other possibility is a problem with the USB installer. I see you are in Oxfordshire. I was at RAL near Harwell/Didcot recently for the STFC open day, if you were close I could have dropped by and checked the iMac/installer.

[Alex Ramsay]

And (an earlier point someone made) - regarding sensor spots, when in the Lightroom develop module you need only click on the retouching brush and then tick the 'visualise spots' option which will appear underneath your picture - much the easiest way to ensure a clean image

 

Alex

[Harry Harrison]

9 hours ago, sb photos said:

I see you are in Oxfordshire. I was at RAL near Harwell/Didcot recently for the STFC open day, if you were close I could have dropped by and checked the iMac/installer.

 

Well it would have been very good to have met another Alamy contributor.  Many thanks for the advice and offer of help, I'll let you know how I get on.  The installer shows up on my friend's MacBook and it came from a seller with good feedback who sells them all the time so I suspect it's OK. Good to rule the keyboard out of the equation also.

 

Thanks again.

[MDM]

 

 

 

29 minutes ago, Mr Standfast said:

 

One of the best posts to a "reasonably new to photography" post I've seen.

 

Suzi, if your first experiences with Alamy QC are bumpy, don't let it put you off photography.

 

Thank you 😀. 

 

Making mistakes is the best way to learn photography I think as long as you remember and don’t repeat them too often. So just dive in. 😎

[suziq]

Thanks all!

 

[Mr Standfast]

11 hours ago, MDM said:

First of all take this positively as it is certainly meant that way. As you are (reasonably) new to photography, if you find yourself asking very basic questions like this, then you should consider the possibility that you are trying to run before you can crawl so to speak. Learning the basics and having a solid grounding in photographic technique is very important if you are attempting to sell your pictures. You don't need to be professional to supply pictures to Alamy but you should be able to produce professional quality pictures. For those of us who catch the photography bug, the experience of learning is amazing and that learning should never end, no matter how long one has been doing it. There are so many people nowadays practising photography in one form or other and it is really worth getting the basics right if one wants to stand out from the crowd. While people here on the forum are very helpful, there are better places than here to learn the craft. Have a good trip 😀.

 

One of the best posts to a "reasonably new to photography" post I've seen.

 

Suzi, if your first experiences with Alamy QC are bumpy, don't let it put you off photography.

[MDM]

1 hour ago, Harry Harrison said:

As someone who doesn't use one, what is the advantage of having one? I appreciate that you can get more things on there at the same time, but apart from that?

 

Or is it in order to watch 4k, 5K 8K.. video?

 

I don't think there is any advantage for stills photography at 27" or less as the pixel density is too high for comfortable viewing in my opinion. I guess there are advantages for video makers if they are shooting at those higher resolutions but not something I know anything much about at the moment. My son got one of the first 5K iMacs when they came out and I've had a few plays with it but I would take my 27" Eizo at 2560 pixels any day with or without a second monitor.

[Harry Harrison]

21 minutes ago, sb photos said:

As 4K and 5K displays are becoming far more common in use

As someone who doesn't use one, what is the advantage of having one? I appreciate that you can get more things on there at the same time, but apart from that?

 

Or is it in order to watch 4k, 5K 8K.. video?

[M.Chapman]

3 minutes ago, sb photos said:

 

As 4K and 5K displays are becoming far more common in use, and will eventually dominate the market, I often wonder what what displays are currently used by picture desks and Alamy for QC?

 

Indeed, perhaps Alamy will need to stipulate exactly what they mean by inspect at 100% in future? Does it mean viewing at 100% (1 image pixel displayed on 1 display pixel) on a display with 100PPI from a viewing distance of around 50cm. Maybe Alamy have already swapped to 200PPI displays and that's why there have been fewer QC fails of late? I haven't heard the screams from offenders being locked in clink for ages. It must be awful lonely in there these days. 

 

Mark

[sb photos]

1 hour ago, M.Chapman said:

 

A minor caveat, if you happen to be using one of those hi resolution 4K monitors (or above) or an Apple Retina display which has pixels so small you can't see them, you may need to inspect at 200%. To inspect your image at 100% it's important that you can (just about) see individual pixels in your image.

 

Mark

 

As 4K and 5K displays are becoming far more common in use, and will eventually dominate the market, I often wonder what what displays are currently used by picture desks and Alamy for QC?

[M.Chapman]

12 hours ago, geogphotos said:

 

Mark, Could you please explain more about this. You always seem to have a good grasp of technical things.

 

I have one of these monitors and although I noticed the difference at 100% when I first started I didn't really understand what was going on. I have not been viewing at 200% and this includes a lot of high ISO shots which I have reduced in size to around 26mb. I haven't had any QC problems. Have I just been lucky? Not sure whether too simply carry on. 

 

Thanks

 

Ian

Hi Ian,

 

A typical (standard resolution) display has around 100 pixels per inch (PPI)

The latest 4K, 5K and retina displays can have pixels that less than half the size at 200 PPI or higher

 

If, for example, a 1000 x 1000 pixel image is displayed at 100% (i.e. each pixel in the image is displayed using single pixels in the display) on a standard display it will be 10" x 10" on screen.

But, if the same image is displayed on a retina display at 100% it will only be 5" x 5". If the viewing distance isn't reduced (to take a "closer look" at the smaller image) the 5 x 5 inch version will appear 2x smaller and hence 2x sharper. You may also not be able to see single pixel defects in the image (CA fringe, dust etc.) as they appear 1/2 the size.

 

However, if the image is displayed at 200% on a retina display it returns to the same size it was displayed on the standard resolution screen. Alternatively the image can be inspected from half the distance, but that may lead to bad posture, neck and back ache!

 

Hope that helps.

 

Mark

[geogphotos]

1 hour ago, M.Chapman said:

 

A minor caveat, if you happen to be using one of those hi resolution 4K monitors (or above) or an Apple Retina display which has pixels so small you can't see them, you may need to inspect at 200%. To inspect your image at 100% it's important that you can (just about) see individual pixels in your image.

 

Mark

 

Mark, Could you please explain more about this. You always seem to have a good grasp of technical things. I use a Canon 5D with 24-105 L

 

I have one of these monitors and although I noticed the difference at 100% when I first started I didn't really understand what was going on. I have not been viewing at 200% and this includes a lot of high ISO shots which I have reduced in size to around 26mb. I haven't had any QC problems at Alamy or anywhere else. Have I just been lucky?  Viewing at 200% now seems odd to me because I am unused to it.  Not sure whether to simply carry on or to change my workflow.

 

Thanks

 

Ian