What is green or blue? How photography affects colours.

[Jamiel]

I have seen various discussions citing specific photographs about what is the most accurate colour for a piece of rolling stock at a certain time. I have also been at TMC when they were trying to replicate the colour of a particular loco and were given an example photo which had to say the least a strange colour tint to it.

I should give a little background about myself to justify what I am talking about. I have worked in the film industry as a Visual Effects Supervisor in film and TV for 18 years, and prior to that in TV and digital imaging for 10 years.

I have a Master’s Degree in Digital Film and Visual Effects and have worked as a lecturer at Leeds Beckett University on their Computer Animation and Visual Effects course.

I have studied and taught quite a bit about what exactly colour is in the digital word. I have also done some print graphics, which use ink as opposed to light to create colour, which is quite different (a subtractive process from white light, as opposed to an additive process from red, green and blue).

 

O.K. I know a bit about colour, but not all about colour. Someone who worked in the paint shop at Doncaster (I presume there was a paint shop at Doncaster) could run rings around me about how to mix colours using paint/pigments. I would really appreciate it if someone did that contribute to the thread to do just that.

 

Anyway I am starting this thread to discuss a little about how a photograph can change the colour of what it represents, and how other factors can also influence how that colour appears. I will try and not get too technical (boring), but pass on a little of my knowledge about colour in photography.

 

One basic thing to note is that daylight during the day is quite blue compared to indoor lighting which is generally quite red. Obviously outdoor light is redder at sunrise and sunset. There are lots of other lighting conditions, and they can all affect how the colour is seen,

 

Here are a few examples of three Bachmann locos I have shot with my Nikon D70s camera with different white balances in slightly different lighting setups.

 

1. Bachmann Blue Class 40. Quite by chance the loco had leaked oil in the box which immediately makes the blue darker and possibly seem more saturated.



A series of images shot outdoors today, sunny with some cloud, with different white balances and some from the light side, some from the shadow side. Some have obvious colour balance issues.

 

 

 

 

 

 

 

 

A series of images with different white balances and some from the light side, some from the shadow side. Some have obvious colour balance issues.

 

 

If I repeat these at night (I will later), or blacked out the windows (as is done on film sets often), then I would get a much redder light.

 

The thing with all these images is that your eye will adjust for the environment by spotting the brightest part of the image and saying that should be near to a pure white. To overcome this I have separated squares of colour from each of the above images and put them side by side. Blue 40 top. Green 40 middle and the slightly less saturated Class 37 bottom. I have also put these on black and white to show how the contrast of the background can affect the perception of the colour.

 

As you can see some of the blues and greens seem to swap according to the white balance. The bottom 7, looks blue to me, yet it is of a green loco. and the top 5 is not very blue anymore. All down to the camera settings.
 

This image takes the three shots of the locos and digitally adjusts the brightness/luminance to roughly match, you can see that such adjustments can change the saturation of the colour.

 

 

In this image I have increased the contrast, I do this to a lot of images (as do publishers) to get the whole image sitting with white and black at the edges of what has been exposed. I have really overdone this to make a point but you can see how increasing the contrast increases the saturation of the colour.

 

 

Similarly when scanning photos or narratives, the setting on the scanner can add in another level of colour balance issues.

Add to that, the time of day, how long the loco has stood in the sun to bleach the colour, if it has had oil or soot coated over it, if it regularly works bricks from red brick factory, or near a mine with a particular tint of ore. All of which I have seen discussed very eloquently.

 

I also asked my American cousin about traditional stills film as he is a photographer.

“A lot colour temperature depends on the processing. The developing machine should be at an industry standard level .... I forget just what that is. Basically there's a standard, but it depends on the processing and how well they maintain their machines. Pro Labs will give the best quality results while drugstores are hit and miss. On cloudy days you can warm up the colour tones by using an orange-pink filter, otherwise you get a cold tone to the image. There's a range of latitude in most 35mm film, so it's not really set in stone, so you can, for example, shoot 400 speed film at 100 or 200 or 600 and develop accordingly.”

My bottom line when looking at photographs or film is what looks like it should be white, and the judge the image according to that. That is exactly what I do at work when putting a studio shot character on green screen into a background shot somewhere else, and I feel it is the same for painting my rolling stock.

The point I am trying to make is that the same colour can change a great deal according to how that patch of colour was photographed and how that photograph is treated afterwards.

I hope this isn't too boring.

I would love to hear what others feel about how they approach using photographs when trying to replicate a loco or rolling stock at a specific time.

Jamie

EDITED for spelling errors.

Edited January 5, 2018 by Jamiel

[Ben Alder]

Sorry I missed this first time around - there are so many gems that vanish into the sea of (choose your own term) that floods the forum every day. I find the aspects of colour rendition fascinating,especially when trying to gauge  a degree of accuracy when studying a picture from the steam age and a grasp of at least the basics of this subject is a must for anyone attempting to replicate a scene. Even when it is somewhere that is personal, not many can hold a colour in their minds with accuracy, especially if decades have passed. Thanks for this explanation.

[New Haven Neil]

What an excellent post.

 

I too missed it the first time around, and came here via Wright Wrights. 

 

A superb description and example of how we don't really know what colour we are looking at in photos.  I recall a thread arguing about what colour 01 001 & 2 were at Holyhead, one person posting a photo that made ne look a dark green colour.  I saw this loco myself, it was black, without a doubt, but many chose to believe the rather poor photo rather than eye witness account!

 

Thank you for your scientific demonstration of the difficulties reproduction of colour presents us with!

[AndyG]

What an excellent post.

 

I too missed it the first time around, and came here via Wright Wrights. 

 

A superb description and example of how we don't really know what colour we are looking at in photos.  I recall a thread arguing about what colour 01 001 & 2 were at Holyhead, one person posting a photo that made ne look a dark green colour.  I saw this loco myself, it was black, without a doubt, but many chose to believe the rather poor photo rather than eye witness account!

 

Thank you for your scientific demonstration of the difficulties reproduction of colour presents us with!

Try 'The Big Four In Colour, 1935-50' (ISBN 1 899816 08 9), for examples of how different film (remember that?) emulsions represented colours. Little wonder that it's so difficult to replicate pre-grouping and pre-nationalisation liveries with no original examples remaining for analysis. I still prefer 35mm for accurate colour rendition over the infinitely tweakable digital alternative. There again as previously mentioned we still have to bear in mind differing colour temperatures during the course of a day, with the blue end of the spectrum more prominent in the morning, and red toward late afternoon, all of which will affect our perception of colour. Then there's aerial perspective to consider...

Edited January 7, 2018 by AndyG

[GeoffAlan]

I've a slight colour vision 'blindness' and particularly in poor light, pretty much everything but bright sunshine, I 'see' some blues and greens as the same colour. So I rely on paint manufacturers getting it right for me. There's nothing I can do to correct this, as it's a genetic fault.

 

However, I can remember BR in the Blood and Custard days and particularly seeing trains of coaches with a wide variation of shades within the general description of Blood and Custard. Apparently the paint faded in use, Given, as the OP states, that, with the unreliable colour rendition of film and digital cameras I'm not sure we can ever be 100% sure we have the right colour on our models. I have personal experience of car paints fading, from a crash repair in the 1980s. So we paint and weather our models and in my case hope!

 

Does it really matter? That is very much a personal choice. 

[New Haven Neil]

Mrs NHN is also colour blind, and agrees that 'Improved Engine Green' is both improved, and green!  Hence my first live steamer was that colour - which it has to be said, photographs digitally very badly, it always looks very much brighter and more orange than it really is especially in full sun, as in this photo.  So don't consider digital media any better than filmstock.

 

[Dunsignalling]

I have seen various discussions citing specific photographs about what is the most accurate colour for a piece of rolling stock at a certain time. I have also been at TMC when they were trying to replicate the colour of a particular loco and were given an example photo which had to say the least a strange colour tint to it.

 

I should give a little background about myself to justify what I am talking about. I have worked in the film industry as a Visual Effects Supervisor in film and TV for 18 years, and prior to that in TV and digital imaging for 10 years.

 

I have a Master’s Degree in Digital Film and Visual Effects and have worked as a lecturer at Leeds Beckett University on their Computer Animation and Visual Effects course.

I have studied and taught quite a bit about what exactly colour is in the digital word. I have also done some print graphics, which use ink as opposed to light to create colour, which is quite different (a subtractive process from white light, as opposed to an additive process from red, green and blue).

 

O.K. I know a bit about colour, but not all about colour. Someone who worked in the paint shop at Doncaster (I presume there was a paint shop at Doncaster) could run rings around me about how to mix colours using paint/pigments. I would really appreciate it if someone did that contribute to the thread to do just that.

 

Anyway I am starting this thread to discuss a little about how a photograph can change the colour of what it represents, and how other factors can also influence how that colour appears. I will try and not get too technical (boring), but pass on a little of my knowledge about colour in photography.

 

One basic thing to note is that daylight during the day is quite blue compared to indoor lighting which is generally quite red. Obviously outdoor light is redder at sunrise and sunset. There are lots of other lighting conditions, and they can all affect how the colour is seen,

 

Here are a few examples of three Bachmann locos I have shot with my Nikon D70s camera with different white balances in slightly different lighting setups.

 

1. Bachmann Blue Class 40. Quite by chance the loco had leaked oil in the box which immediately makes the blue darker and possibly seem more saturated.

 

 

A series of images shot outdoors today, sunny with some cloud, with different white balances and some from the light side, some from the shadow side. Some have obvious colour balance issues.

 

 

 

 

 

 

 

 

 

A series of images with different white balances and some from the light side, some from the shadow side. Some have obvious colour balance issues.

 

 

 

 

If I repeat these at night (I will later), or blacked out the windows (as is done on film sets often), then I would get a much redder light.

 

The thing with all these images is that your eye will adjust for the environment by spotting the brightest part of the image and saying that should be near to a pure white. To overcome this I have separated squares of colour from each of the above images and put them side by side. Blue 40 top. Green 40 middle and the slightly less saturated Class 37 bottom. I have also put these on black and white to show how the contrast of the background can affect the perception of the colour.

 

As you can see some of the blues and greens seem to swap according to the white balance. The bottom 7, looks blue to me, yet it is of a green loco. and the top 5 is not very blue anymore. All down to the camera settings.

 

This image takes the three shots of the locos and digitally adjusts the brightness/luminance to roughly match, you can see that such adjustments can change the saturation of the colour.

 

 

In this image I have increased the contrast, I do this to a lot of images (as do publishers) to get the whole image sitting with white and black at the edges of what has been exposed. I have really overdone this to make a point but you can see how increasing the contrast increases the saturation of the colour.

 

 

Similarly when scanning photos or narratives, the setting on the scanner can add in another level of colour balance issues.

Add to that, the time of day, how long the loco has stood in the sun to bleach the colour, if it has had oil or soot coated over it, if it regularly works bricks from red brick factory, or near a mine with a particular tint of ore. All of which I have seen discussed very eloquently.

 

I also asked my American cousin about traditional stills film as he is a photographer.

“A lot colour temperature depends on the processing. The developing machine should be at an industry standard level .... I forget just what that is. Basically there's a standard, but it depends on the processing and how well they maintain their machines. Pro Labs will give the best quality results while drugstores are hit and miss. On cloudy days you can warm up the colour tones by using an orange-pink filter, otherwise you get a cold tone to the image. There's a range of latitude in most 35mm film, so it's not really set in stone, so you can, for example, shoot 400 speed film at 100 or 200 or 600 and develop accordingly.”

 

My bottom line when looking at photographs or film is what looks like it should be white, and the judge the image according to that. That is exactly what I do at work when putting a studio shot character on green screen into a background shot somewhere else, and I feel it is the same for painting my rolling stock.

 

The point I am trying to make is that the same colour can change a great deal according to how that patch of colour was photographed and how that photograph is treated afterwards.

 

I hope this isn't too boring.

 

I would love to hear what others feel about how they approach using photographs when trying to replicate a loco or rolling stock at a specific time.

 

Jamie

 

EDITED for spelling errors.

From the evidence of your photos, I'll carry on leaving the White Balance on auto, though the ones taken on "cloudy" look good, too.

 

I very seldom feel any need to tweak the colour when printing unless I'm using cheapo ink cartridges. 

 

Cameras: Nikon D5000 SLR, Lumix LX100 compact, printer: Canon

 

John

Edited January 7, 2018 by Dunsignalling

[Jamiel]

Mt point was mostly that when looking at historical photographs of engines the same set of criteria affect the image. Although the photographs were on physical film stock, different stocks had the same effect as the different colour balances on a digital camera. That plus the ageing process, fading and then how the printing of the negative was handled, on to what print paper etc.

It is also worth remembering that some early colour film stock was very saturated/vivid compared to modern colour imaging. I am not sure if this was to overemphasise the fact they were colour or just that the early colour film was not as good at keeping colour under control.

Together with all the variables I mentioned in the original post mean that an exact colour to match to in a photograph has had a journey from the original colour of the locomotive through different twits and turns to get to the image you are looking when mixing your colour to match on the model before you.

Whoever said that photographs do not lie, was easily convinced!

Jamie

Edited January 7, 2018 by Jamiel

[Dunsignalling]

Mt point was mostly that when looking at historical photographs of engines the same set of criteria affect the image. Although the photographs were on physical film stock, different stocks had the same effect as the different colour balances on a digital camera. That plus the ageing process, fading and then how the printing of the negative was handled, on to what print paper etc.

 

It is also worth remembering that some early colour film stock was very saturated/vivid compared to modern colour imaging. I am not sure if this was to overemphasise the fact they were colour or just that the early colour film was not as good at keeping colour under control.

 

Together with all the variables I mentioned in the original post mean that an exact colour to match to in a photograph has had a journey from the original colour of the locomotive through different twits and turns to get to the image you are looking when mixing your colour to match on the model before you.

 

Whoever said that photographs do not lie, was easily convinced!

 

Jamie

TBH I treat anything taken on old colour film with caution and anything not taken on Kodachrome with extreme caution.

 

Added to which, many colour reproductions for books are taken from copies rather than original slides.

 

John

[Quarryscapes]

Every aspect of the imaging process from start to end has an effect on what you see, and that includes your eyes.

 

Film emulsions work very differently to digital - on a sensor you have photosites under coloured filters each reacting to the light that corresponds with that colour of filter, each unaffected by each other (in theory!), but on film the sensitive bits are coated in layers over each other with filters in between so there is a lot of scope just there to alter the way light is captured, without delving into development processes or how the resulting negative is then used. Traditionally colour negs would have been printed with a filter to take out the orange mask and a human would select filters and paper to balance the colour and contrast, so you were never actually getting a direct negative of the negative.

 

These days negatives are scanned and digitally auto levelled, which brings in a whole host of it's own colour shifts. If you're doing it yourself a good way to lock the colour for the whole roll is to shoot a blank frame, and select that as the basis for removing the orange mask for the entire roll. If you do that, then you may well find that certain films exhibit changes of colour with changing exposure! 

[Jamiel]

Interesting about the orange tint. Could this be a compensation for using daylight stock with incandescent lights?

With physical film (moving picture film) there were two types of stock, daylight and tungsten. Filters has to be used on lights to compensate for which stock was used. Daylight stock matches the much bluer light of daytime sun, and tungsten matches the more orange light of artificial film lights.

Doing a white balance with a digital camera is a compensation for this as well as setting where the top end of your exposure should be.

It really is a huge area of expertise, which to go into great depth you would need a cinemtaogrpher. I would ask my friend Bart who I am filming with in a few weeks, but I suspect he would point me to a whole book on the subject.

Jamie