White vs Grey paper for gelled lighting

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Having just bought a roll of grey paper* I was interested to stumble across this article claiming white gives better results than grey with gels, especially when using pastel tones:
http://jakehicksphotography.com/lat...a-white-or-grey-background-with-coloured-gels

What are the panel's thoughts?

I have a lot of respect for the amount of testing Jake Hicks does but I don't always agree with his reasoning.

*I bought grey 'cos I wanted grey; usability with gels is a nicety.
 



The great advantages of the grey paper is that it produces
rich colours in more controllable fashions. The drawback is
the eventual higher light power but it still, then, preserves all
its control quality thanks to the inverse square law. The same
law applies with white paper and the required power is less but
with much higher light reflectance… may contaminate the set.
 
High end projector screens are grey as it improves contrast and saturation & for me if I could only have one background roll, albeit paper or vinyl it would be grey - oh actually I do only have one background roll, care to guess the colour.
I didn't bother reading the article because the right outcome should have been grey....;)
 
I've just remembered, I made a video about using light gels a while ago - on a grey background, obviously:)
 
The grey background images look like the backgrounds wasn't actually flat, but slightly crumpled - there are irregular areas showing through, rather than the smooth background with the white?
 
Obviously, white is more reflective and therefore will be better for reflecting the gelled color. Plus, white tends to be truer to color than a lot of grey/black BGs.

But the problem not addressed is controlling power/ratios... in order to get saturated colors from a white BG you have to really drop the exposure hard for something that is white *plus* added light. Is the lighting on the BG really more important than the lighting of the subject? Or even equally important? Depending on the subject/separation/ambient it can be very hard to get the balance you want. If you have enough of the right equipment (which may well include ND's and different power strobes/strobes with wide range of adjustability), and great control of the ambient (blackout), it should be doable reliably/consistently.
 
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Did anyone actually read the article?

To my eye just test images on white look more pleasing than those on grey. At the moment I can't understand why - unless the grey wasn't actually pure grey.
I think it's kind of like the ISL compounded... white reflects all of the light, darker colors absorb some of the light. Darker colors are going to compound the rate of falloff, perhaps not evenly.
 
First of all, I don't know squat about gelling... but I had a brief peruse of the article.
From what I remember from my Manfrotto days, I was always told that grey is best for gelling, but I much prefer the results as shown in the article from using white.
 
First of all, I don't know squat about gelling... but I had a brief peruse of the article.
From what I remember from my Manfrotto days, I was always told that grey is best for gelling, but I much prefer the results as shown in the article from using white.

Agreed but it appears the difference is more to do with improper testing technique than the colour of the background.
 
Did anyone actually read the article?

To my eye just test images on white look more pleasing than those on grey. At the moment I can't understand why - unless the grey wasn't actually pure grey.
Yes, I read it.
But when people write articles/make videos then they should let the facts do the talking, not use PS to paint a picture.

It must be obvious to everyone that white can only produce pastel shades (unless the subject is entirely backlit or sidelit) and that grey can do that equally well, plus a lot more..
Frankly, I think that you've overthinking this.
 
The "mid grey" vinyls and papers I've used seem to be more like 2-3 stops under white, and if I've understood what Jake is saying correctly, he added one stop of light to each shot on grey vs the equivalent shot in the chart, on white. This isn't enough, and if you look at a shot on the white chart, and then go 2 rows up on the grey, they are indeed roughly the same (somewhere between 2 and 3 rows up I reckon). I also suspect he used a white wall and a grey paper - there are no creases on the white chart - which makes it much more attractive.

I've noticed a lot of this "feelings over facts" creeping in on blogs and vlogs - I watched one last night where the photographer claimed LED lights just gave a much softer light than flash... (his LED lights were much bigger that a typical speed-light, but the way he says it implies there's some magic in the way the light is produced rather than simply the comparative sizes of the light sources).
 
I've noticed a lot of this "feelings over facts" creeping in on blogs and vlogs - I watched one last night where the photographer claimed LED lights just gave a much softer light than flash... (his LED lights were much bigger that a typical speed-light, but the way he says it implies there's some magic in the way the light is produced rather than simply the comparative sizes of the light sources).
Yes, and this happens all the time. There are constant subjective opinions, masquerading as facts, in marketing material produced on behalf of manufactuers by 'influencers' (people who manufacturers use to con the buying public into buying their products).
Some lenses are 'the sharpest', lights are 'the brightest' and lights have "better quality of light" - but with no data to support any of these claims, many of which cannot be supported simply because the immutable laws of physics tell us that they cannot possibly be true - so, to 'prove' their point, these people show photos that have been heavily manipulated and which, in some cases, obviously weren't even produced on the equipment that they claim to have used...

So, not so much "feelings over facts", more ignorance of facts (assuming honest intent) or, more likely, false marketing.
 
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The internet is free, so anyone can post a review or blog regardless of their qualifications (or intentions) and unfortunately a lot of people do. But that aside, it takes a great deal of time and effort to do things properly, which costs money, and there's not a lot of that about on the free internet.
 
The internet is free, so anyone can post a review or blog regardless of their qualifications (or intentions) and unfortunately a lot of people do. But that aside, it takes a great deal of time and effort to do things properly, which costs money, and there's not a lot of that about on the free internet.

For this subject think of the Internet like an all you can eat buffet, sure most of it's been prepared by an enthusiastic beginner and most of it is decent enough (a little bit of food poisoning from time to time) with amazing variety but if you only had the professionals preparing it you'd probably end up starving to death no matter how good the occasional meal is.
 
I'd say it was more like an endless buffet but 90% of the food contains no nourishment, 5% is worth eating and 5% really hits the spot. Problem is, you don't know which is which.

What we end up doing is sifting out the rubbish with experience, by going to trusted websites, reliable bloggers and posters that we know by their user name to have good knowledge. But for the newcomer, it's a needle in a haystack.
 
For this subject think of the Internet like an all you can eat buffet, sure most of it's been prepared by an enthusiastic beginner and most of it is decent enough (a little bit of food poisoning from time to time) with amazing variety but if you only had the professionals preparing it you'd probably end up starving to death no matter how good the occasional meal is.
Up to a point, yes - but we didn't starve before the internet came along:)
Back in the bad old days when all that we had was the dead tree press, there was a much smaller pool of information, but the information that was published was generally pretty good.
It had to be good because the publishers wouldn't accept manuscripts from dreamers, con artists and the like - those of us who were published knew our stuff and had already established a reputation, because unless the author already had a reputation, the books simply wouldn't sell and the publishers would lose money.
And, once the deal had been done, the work would go to an editor, who would - well, edit, and these editors were incredibly annoying people who sometimes watered down the book and seriously p***ed off the authors, but at least they acted as a filter, ensuring that the contents were accurate. I know this because, as well as suffering at the pen of editors, I've also been an editor.

The dead tree press isn't yet totally dead - take Light: Science & Magic as an example - it sells well, because it's good, and there is still a market for it, notwithstanding all the videos and tutorials available free online.

The apparent problem with the old way of doing things was the year or so that it took to get a book published, which meant that it was never up to date in terms of new technology, but that wasn't really much of a problem because the rate of technological improvement used to be very slow.
I'd say it was more like an endless buffet but 90% of the food contains no nourishment, 5% is worth eating and 5% really hits the spot. Problem is, you don't know which is which.

What we end up doing is sifting out the rubbish with experience, by going to trusted websites, reliable bloggers and posters that we know by their user name to have good knowledge. But for the newcomer, it's a needle in a haystack.
As you say, for the newcomer it's difficult if not impossible to sort the wheat from the chaff. With the internet, it's all about presentation and b******t, with 'influencers' (who usually fail to mention that they are being paid) dancing to the tune of their paymasters and actively deceiving the people who they rreach out to.
Again, and turning now to photographic magazines, a few years ago any paid for content was clearly labelled as such, but although still labelled, paid for content is now far less obvious to the average reader. This is understandable beause the magazines are struggling to survive and they need to attract more and more paid for content, but it isn't right. And, increasingly, their own level of knowledge is much lower than it used to be, they rely more and more on staffers who know little if anything about their subject and who contribute to a range of different specialist publications owned by the group, which mans that the same person may write technical articles for Caravanning Monthly, Fly Fishing weekly and a photography magazine. All is not completely lost, there are still a few real experts around, and there is one on this forum
 
Darker colors are going to compound the rate of falloff, perhaps not evenly.

Why? I'm having trouble thinking my way through the physics of this

Agreed but it appears the difference is more to do with improper testing technique than the colour of the background.

So what should he have done differently?

I'd say it was more like an endless buffet but 90% of the food contains no nourishment, 5% is worth eating and 5% really hits the spot. Problem is, you don't know which is which.

What we end up doing is sifting out the rubbish with experience, by going to trusted websites, reliable bloggers and posters that we know by their user name to have good knowledge. But for the newcomer, it's a needle in a haystack.

Exactly.. that's why I'm here.

Back in the bad old days when all that we had was the dead tree press, there was a much smaller pool of information, but the information that was published was generally pretty good.

Generally pretty good.. but I do have a couple of older books which are complete tosh & full of misunderstandings & inaccuracies.
 
Should they ever post please let us know ;)
I was obviously referring to Richard Hopkins... in case you haven't noticed, he does in fact post quite often.
 
Why? I'm having trouble thinking my way through the physics of this



So what should he have done differently?



Exactly.. that's why I'm here.



Generally pretty good.. but I do have a couple of older books which are complete tosh & full of misunderstandings & inaccuracies.
O.K., so you've got a couple of my old books... throw them away :)
But what I said does generally hold good, and it's a numbers game.
There will be maybe 5% of useless books, compared perhaps to 95% of useless internet content.
 
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They say expert, ex as in has been and spurt as in a drip under pressure :p
Confucius he say: when you've dug yourself into a hole, it's time to stop digging.

BTW, did you ever answer Richard's question about who now owns godox.co.uk ?
 
Why? I'm having trouble thinking my way through the physics of this
I don't know the physics behind it... it's just experience/impression.
Doing my best to make sense of it; dark surfaces absorb light so they require more light for a given level of (reflected) illumination. And a stop of light is a doubling of power, i.e. there is much less difference in power/light between a stop of light at the dark end than there is at the bright end. So absorbing more light is going to be more apparent at the dark end, i.e. the rate of falloff.
Comparing the results the transitions are a bit harder/more rapid on the grey BG, and I'm sure it would be even harder/faster if the BG was darker to start with. Lighter colors seem to show this effect more, probably because they are brighter and for a given level of saturation they require a lower power setting.

So what should he have done differently?
One could argue that not enough light was added for the grey background to make the areas of coverage/exposures (more) equal. I.e. mid grey is ~ 2 stops below white but he only added 1 stop of light... and looking at the results it looks like one stop less on the white is a closer match. Comparing the bottom 4 rows on white to the top 4 rows on grey looks to be more equivalent. Plus, it would have been nice if the grey BG was also smoothed out like the white was.
 
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So what should he have done differently?

At the very least make sure both surfaces were consistent otherwise when you look at the photos the white appears better simply because it's flat.

It's supposed to be a comparison of a white and a grey background but it seems to be more of a test of what happens when you put a standard reflector a little close to a background, more of a comparison for that arrangement rather than the background.
 
Darker-toned backgrounds give more control when gelled, with a tighter pool of light and more pronounced fall-off.

1) With a white background and no light directly on it (just random spill from other lights) it will usually reproduce as a light grey tone. This is the darkest it can ever get, so only suitable for lighter, pastel gels - yellow, pink etc. Grey will obviously reproduce much darker, so there's more scope for darker gels like red and blue.

2) With a white and a darker background, even when the brightest zone in the centre is adjusted to the same level, the darker background will have a relatively greater influence as the brightness reduces towards the edges - so the pool of light appears smaller with more pronounced fall-off.

These two images are white matt (top ) and slate grey matt (close to 18% grey) below. They're both Manfrotto Colormatt backgrounds, same material, same surface texture. Lit with a studio head (just visible at the bottom) and snoot from about 3ft distance, and the pool of light is about 2ft across. No gels, they're just a distraction for this. Same camera settings, only flash power increased for the grey background so that brightness in the centre is identical.

White
white-6644.jpg

Mid grey
mid grey-6650.jpg
 
2) With a white and a darker background, even when the brightest zone in the centre is adjusted to the same level, the darker background will have a relatively greater influence as the brightness reduces towards the edges - so the pool of light appears smaller with more pronounced fall-off.

Thank you! Obvious really, I'm embarrassed I couldn't see that for myself. I should have just done the maths, that would have made it clear.
 
Thank you! Obvious really, I'm embarrassed I couldn't see that for myself. I should have just done the maths, that would have made it clear.

This doesn't sit quite right with me now! Point 1 is okay, and so is point 2 but maybe for different reasons. The increased fall-off with grey is clearly there, and that's what matters in practise, but there are other factors influencing it, eg spill from the white ceiling.

I'll have another go later, try a couple of other things ;)
 
This doesn't sit quite right with me now! Point 1 is okay, and so is point 2 but maybe for different reasons. The increased fall-off with grey is clearly there, and that's what matters in practise, but there are other factors influencing it, eg spill from the white ceiling.

I'll have another go later, try a couple of other things ;)
I (sort of) did the math to make sense of it... here's the thing, the grey BG isn't absorbing "2 stops." It is absorbing a certain quantity of light (lux, photons/sec) that equates to two stops for whatever was metered (i.e. highlights). And if it is absorbing 2 stops worth of photons/sec from the highlights it is also absorbing the same 2 stops worth of photons/sec everywhere else. There are certainly other things that play into it as well (angles/textures/material, etc).

The first three lines are in lux (photons per second) using low/arbitrary numbers representing the logarithmic increase for the 5 stops of light represented in a histogram. They also represent 1/2 of the area of coverage. The output for the grey BG is increased two stops for the highlights, and due to the spread/falloff of the output it is also increased by two stops everywhere else (in lux). But the grey BG is absorbing the same number of lux (48) across the entire area which gives us the highlight at the same level of exposure, but a much more rapid rate of falloff.
The last line shows the compression of the gradient as 5 stops as it would be reported by a histogram (not in lux). The histogram would actually be full width but of lower height rather than compressed horizontally. I.e. the histogram is always going to show the same 5 stops between black and white, and it would meter that way as well.

Untitled-2.jpg

However, no matter how I try to work this out, what units I use (lux/candela/EV), or how large of quantities I use, it always comes up w/ the grey BG reflecting only the highlight stop in lux (3rd line) and it is much more abrupt/drastic than reality. So I think there is some kind of error (it may just be the "spacing" of the stops?).

Edit: full stop measures are really quite coarse for gradients... that's probably contributing to the "abruptness" in the example. And it is probably not true that an increase in output will be increased evenly with exactly the same spread/falloff across the area of coverage (reflector/bulb dependent). I.e. the second line might look more like 3, 8, 24, 56, 64 after the two stop increase for the highlights.
 
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