Merging multiple layers for time lapse

[ermintrude]

OK further to the time lapse idea I need to be able to superimpose the layers to form an image with of the total of all layers. As a tester I tried it with 5 layers and set opacity to 20% for each. This is obviously not the correct answer!

How is it done properly, preferably with straight photoshop and no additional addons?

[Stevet]

Hi Erm,

Not sure what exactly you are doing, but have you tried having multiple 100% opacity layers, then using a layer mask (or the eraser tool, or...) to remove unwanted areas of the uppermost layers ? (layer masks are my favourite as you can come back to them later and remove more/add some back if you wish.

Depending on the effect you are after, you might then want to play about with layer opacity.

HTH

[ermintrude]

Hi

What Im after is seeing every image in one so that the things that remain still will look the same but the things that are moving will become invisible.

I know that with long exposure things that move will become invisible anyway, but to achieve the point of the project they would have to be multiple 'shots in time' and not a period of time. Chopping time up if you like and then superimposing it to see that some of it always remains the same.

So masking isnt an option, Im not really after any photographic potential in itself, its just an idea for an art project Im doing.

Imagine shooting a clock every minute (I know I could do this easier than one every minute but the point of the project would be *if* I did one every minute) How would I superimpose all the pictures so the final image looked like an actual normal photo but without hands.

I know somebody did this with a face but I cant remember their name - faces of lots of people, maybe over a hundred? It was probably done on film but the principle is the same, what should the exposure be for each image to make the final picture look 100%?

[john_g]

I'm wondering whether HDR software might do what you want... I think some of them have a feature where, when you merge the images, ghosts are removed. And there's no need to do tone-mapping, so your picture wouldn't have that HDR look.

[ermintrude]

I'm wondering whether HDR software might do what you want... I think some of them have a feature where, when you merge the images, ghosts are removed. And there's no need to do tone-mapping, so your picture wouldn't have that HDR look.

mmm but I'd specifically want any ghosts to stay. I want WYSIWYG. Everything that was there stays there, but something like a clock hand which you would think pretty solid will disappear.

Ive found a site that says just reduce each layer by the appropriate amount so eg 5 laters = 100%, 80%, 60%, 40%, 20% which seems to work OKish. Not sure how well it would work wioth a really large amount of images tho, plus its fiddly, but hey...

Ive got the camera in the corner at the mo doing 60 shots over the course of an hour so Ill see what they look like at the end and how easy it is to do anything with. If the battery lasts that long Why oh why oh WHY do they not supply you with a mains adaptor I have a universal AC/DC adapter but out of all the connectors NONE fit the C*n*n...

[Norman]

An image with 60 layers is going to be BIG.

[ermintrude]

Depends, I dont need them full size tifs so I could make a small jpeg and maybe merge bunches of layers at a time and then layer the bunches... we shall see It might all go a bit Conference...

[Fen]

Ive got the camera in the corner at the mo doing 60 shots over the course of an hour so Ill see what they look like at the end and how easy it is to do anything with.

One other thing to note...

You need constant lighting to it's the same throughout the shot, otherwise you'll get different shades/tones from the start to the finish.

[Fen]

I forgot to do that myself once and had to reshoot everything

[geoffL]

Seems to me this could be done using the layers advice in the second post. They layers (all 60 of them !!) can still display at 100%. However you would then need to mask out the moving element wach time. In the case of the clock, mask out the hand on the '5 minutes past' so you can see the space the previously occupied the 5 past mark as it appears in the 4 minuts past image etc.

That would work - if I understood you properly...! Derpending on how much was moving in the pic you might have quite a bit of work to do though.... could be interesting though.

[beejaybee]

I think you may be able to get this effect with little effort using Registax (a free astronomical image processing program). Just use non-moving objects to align the images together then stack them - the moving objects will appear multiple times in the stacked image. The current version of Registax will work with TIFF and JPEG images but not with RAW and has an (undocumented) restriction, the long side of the frame must not exceed 4096 pixels. Anyway it may be worth a try.

Free download here.

[ermintrude]

One other thing to note...

You need constant lighting to it's the same throughout the shot, otherwise you'll get different shades/tones from the start to the finish.

Yeah I thought about that but it is supposed to be about real life - it is a record of life over eh 24 hours so yes some of the time it will be dark! Im not aiming for an aesthetically pleasing photograph so it doesnt matter if it looks rubbish. For the clock one I was planning to leave it inside with the light on for 12h or whatever but if I do the real life one that will have to include darkness at night.

[ermintrude]

Seems to me this could be done using the layers advice in the second post. They layers (all 60 of them !!) can still display at 100%. However you would then need to mask out the moving element wach time. In the case of the clock, mask out the hand on the '5 minutes past' so you can see the space the previously occupied the 5 past mark as it appears in the 4 minuts past image etc.

That would work - if I understood you properly...! Derpending on how much was moving in the pic you might have quite a bit of work to do though.... could be interesting though.

Sorry no, masking is absolutely out of the question. As I mentioned it does not have to be aesthetically pleasing it needs to be a record of time. I dont care if all the lights go out or a monkey cr@ppes on the photo, everything must be in there. All I want to know is the best way to superimpose to give the relevant 'exposure' to each shot in the stack.

On a large number of images it just isnt happening, if I do the 100/80/60/40/20 % route on a stack of 60 you only see the top third. So I tried doing 2/3 of the one below ie (from bottom up) 100, 66, 44, 30, 20, 13, 9, 6, 4, 3 etc etc etc.
Im sure it must be like the cube root or the log or something mathematical that I cannot even begin to think about...where's John when you need him??!

[ermintrude]

I think you may be able to get this effect with little effort using Registax (a free astronomical image processing program). Just use non-moving objects to align the images together then stack them - the moving objects will appear multiple times in the stacked image. The current version of Registax will work with TIFF and JPEG images but not with RAW and has an (undocumented) restriction, the long side of the frame must not exceed 4096 pixels. Anyway it may be worth a try.

Free download here.

Hi, thanks for that Ill have a look. However its not so much the alignment Im after but the exposure. the thing is on a tripod so it isnt going anywhere and the clock will remain in the same place even though the hands are moving. I just nbeed to know how to make everything have an equal exposure in a stack as dividing it in various ways doesnt seem to work.

Whacking the contrast a touch, over an hour I get this

However before the levels etc I can still see variations in balance ie the most recent or something will still be clearer. This one is the thirds one I described above:

[ermintrude]

PS I also have a movement problem. The tripod/camera doesnt seem to be totally still. Most of the time it is OK but suddenly it'll shift a millimetre or two - is this due to the shutter or something else?

[beejaybee]

The tripod/camera doesnt seem to be totally still. Most of the time it is OK but suddenly it'll shift a millimetre or two - is this due to the shutter or something else?

Poltergeists!

Doesn't matter though. Registax will automatically align all your frames for you. Zoom out a touch, or move the camera back from the subject, so that you can trim off the edges which haven't registered on all the frames.

[john_g]

I've been thinking about this and have come to the following conclusions... although they might not be correct!

If you want to stack lots of layers in this way, you're not going to be able to do it all in one go - the control over opacity just isn't precise enough. I know it'll sound like a lot of work, but I think I'd blend layers in pairs, using an opacity of 50%, then use 'merge down' to flatten that pair and repeat with the next pair until you've halved the original number of layers. Then repeat the above, again using 50% opacity and again reducing the number of layers by half. and so on. If you started with, say, 128 layers, you'd only need to go round this loop 7 times, so I don't think it's impossible. Maybe you could reduce the workload by blending 4 layers at a time.

But... at the end of the day, if you photograph your clock every minute for an hour and blend the resulting images, the minute hand will be in a unique position for each image (assuming no overlap of the hand between shots) and so the stacked image will show the hand in any given position in just one shot whilst the other 59 will show the clock face behind the hand. So the hand is hardly going to show, if at all.

If this is what you want then no problem but if you want to overcome this I can't see any option but to either mask or apply some obscure Photoshop blending option that I know nothing about and which may, or may not, exist. Mind you, I've only got Elements 4 so maybe CS2/3 can do exactly what you need.

[beejaybee]

the stacked image will show the hand in any given position in just one shot whilst the other 59 will show the clock face behind the hand. So the hand is hardly going to show, if at all.

Perhaps white hands on a dark dial would work better.

Anyway I decided to try producing a stacked timelapse image using Registax, here is is:


Told Registax to do a single point alignment on the centre of the dial, adjusted the quality filter as it wanted to discard a couple of the images, then let Registax get on with the stacking - just saved afterwards, then reduced size to suit this forum in a different program. Took me maybe a minute's work on the computer.

[ermintrude]

I've been thinking about this and have come to the following conclusions... although they might not be correct!

If you want to stack lots of layers in this way, you're not going to be able to do it all in one go - the control over opacity just isn't precise enough. I know it'll sound like a lot of work, but I think I'd blend layers in pairs, using an opacity of 50%, then use 'merge down' to flatten that pair and repeat with the next pair until you've halved the original number of layers. Then repeat the above, again using 50% opacity and again reducing the number of layers by half. and so on. If you started with, say, 128 layers, you'd only need to go round this loop 7 times, so I don't think it's impossible. Maybe you could reduce the workload by blending 4 layers at a time.

OK Ill give that aa go. The example above was done by merging 5 layers at a time 100/80/60/40/20(and flattening each file) then merging those 20 files in various combinations but as you can see I havent gotten the right balance.

But... at the end of the day, if you photograph your clock every minute for an hour and blend the resulting images, the minute hand will be in a unique position for each image (assuming no overlap of the hand between shots) and so the stacked image will show the hand in any given position in just one shot whilst the other 59 will show the clock face behind the hand. So the hand is hardly going to show, if at all.

Exactly!! This is exactly the point! Nobody seems to be understanding me wanting a photo of 'nothing' but that is exactly the point, I am looking at the existence of time, the subjectivity of it, time vs temporality etc so this is one way of investigating or illustrating it. I appreciate I could mask bits out but its really not the point of the exercise.

Like here - this is over one hour so the minute hand is almost invisible if I can get the exposure right (its actually inivisible on here due to levels adjustment etc) but if I could do it over 12h the hour hand would also be invisible. The only reason you can see the second hand is because the photo was taken every minute - at the same point every minute.

Cheers for the help anyway, Ill give it a go.

[Fen]

"I am looking at the existence of time"

Time doesn't exist.