Experiments in monochrone

[Compound2632]

47 minutes ago, Mikkel said:

The D299, on the other hand!

 

Just noticed that sports the dreadful Fox transfers! (It's the M that is particularly unlike anything seen on the real thing.)

[57xx]

8 hours ago, Mikkel said:

 

Many thanks. Hard to tell the dark grey MSWJR from the GWR red wagons. The D299, on the other hand!

 

 

Also not how much darker the cart in the foreground is than the wagons.

 

Here are your other 2 pics.

 

 

In the bottom pic, we can see some of the shortcomings of the filter. I would expect the sky to be whiter, I could make it so blue/cyan appears paler but then it would throw off my reference pic. It's possible my reference is showing a more modern orthographic film that isn't as sensitive to blue as older emulsions were. Some of the information I found did suggest the earliest emulsions were very blue sensitive, hence why Nick's period picture shows a blown out sky.

[magmouse]

5 minutes ago, 57xx said:

In the bottom pic, we can see some of the shortcomings of the filter. I would expect the sky to be whiter

Not necessarily a shortcoming of the filter - Mikkel’s pictures don’t include real sky, and so may not have realistic relative tones between sky and ground. I think the tone of the ground throws the eye off somewhat - it makes sense in colour, but in mono it seems odd to have such a pale colour for the ground.

 

Nick.

[57xx]

Here's what I've been working to as references:

 

 

The top row is from a commercial Photoshop plugin. The bottom two pics are my interpretations. I've still not got the greens quite right on the ortho, but every time I try and lighten darker areas, the lighter bits wash out. Still getting the hang of the hue/saturation layer!

[57xx]

14 minutes ago, magmouse said:

Not necessarily a shortcoming of the filter - Mikkel’s pictures don’t include real sky, and so may not have realistic relative tones between sky and ground. I think the tone of the ground throws the eye off somewhat - it makes sense in colour, but in mono it seems odd to have such a pale colour for the ground.

 

Nick.

 

I suppose there is also a difference in trying to get a general sense of colour renditions vs trying to perfectly replicate an old photo as with the Iron Duke.

[Mikkel]

On 04/08/2023 at 16:01, Compound2632 said:

Just noticed that sports the dreadful Fox transfers! (It's the M that is particularly unlike anything seen on the real thing.)

 

Well spotted. It has been on the to do list since approx. 2017. Let's give it another 4 years to make it a nice round number.

 

 

 

On 04/08/2023 at 23:52, 57xx said:

 

 

Also not how much darker the cart in the foreground is than the wagons.

 

Here are your other 2 pics.

 

 

In the bottom pic, we can see some of the shortcomings of the filter. I would expect the sky to be whiter, I could make it so blue/cyan appears paler but then it would throw off my reference pic. It's possible my reference is showing a more modern orthographic film that isn't as sensitive to blue as older emulsions were. Some of the information I found did suggest the earliest emulsions were very blue sensitive, hence why Nick's period picture shows a blown out sky.

 

Thanks! It's interesting how clearly the ortho filters capture different shades of grey here. The MR and Weedon wagons stand out much lighter than the red wagons, the MSWJR wagon comes across more or less the same as the reds, while the brake van is much darker than the reds.

 

I suppose that illustrates how different stages of weathering can make wagons look very different in period photos.

 

But of course as Nick also alludes to, these are models in an artificial context taken with a mediocre camera, so a lot of things could affect the output. 

 

Edited August 6, 2023 by Mikkel
To clarify

[kitpw]

Some experiments:

taking the process as a dark room process rather than a 'taking-pictures' process, akin to printing a colur picture in black & white on panchromatic or orthochromatic paper, Photoshop 'channels' rather than filters allows the removal of different colour sensitivities and relies only on the Photoshop algorithm.  The Iron Duke picture can be "printed" with only the blue channel and looks like this:

It can also go through some post production, using the RAW filter to increase 'haze':

which approximates to the polluted environment which was commonplace in the photos we are used to looking at from the late C19th. It can be increased as required.

 

Using the same processes in Photoshop on one of the Farthing pictures - blue channel only:

...and with added haze and a minor reduction in 'clarity' (which isn't the same as blur):

In Photoshop, the process requires the colour channels to be duplicated and the originals deleted.  The blue channel can then be selected and the other duplicated channels deleted.  The image then needs to be copied and pasted to a new file and the channels tab will show only a gray channel.  The post-production is user determined where the transition to b & w is algorithm based - I'm not certain but I think that the channel deletions produce ortho rather than panchromatic "paper" as clouds do not appear in the Iron Duke picture.  Mikkel's sky is post-production in the original (I think).  I haven't tried this out in DarkTable as I don't yet have much experience of it.  What is clear, I think, is that all the colurs are rendered only on the basis of their original tonal quantity/quality when tint is no longer a permitted parameter.

[kitpw]

A few further experiments in monochrome....

The grey chart is the same colour chart rendered into b & w in the same way

as the Iron Duke picture above.

 

Just to illustrate how greys (or is it grays?) are influenced by what's around them. 

All the larger grey squares are the same square repeated in different parts of the grid.

(There's a small light grey square crept in...don't know where that came from).

Although the're the same grey square, they look darker or lighter depending

on where they are on the grid.

 

 

 

 

 

 

 

 

[57xx]

7 hours ago, kitpw said:

Some experiments:

taking the process as a dark room process rather than a 'taking-pictures' process, akin to printing a colur picture in black & white on panchromatic or orthochromatic paper, Photoshop 'channels' rather than filters allows the removal of different colour sensitivities and relies only on the Photoshop algorithm.  The Iron Duke picture can be "printed" with only the blue channel and looks like this:

It can also go through some post production, using the RAW filter to increase 'haze':

which approximates to the polluted environment which was commonplace in the photos we are used to looking at from the late C19th. It can be increased as required.

 

Using the same processes in Photoshop on one of the Farthing pictures - blue channel only:

...and with added haze and a minor reduction in 'clarity' (which isn't the same as blur):

In Photoshop, the process requires the colour channels to be duplicated and the originals deleted.  The blue channel can then be selected and the other duplicated channels deleted.  The image then needs to be copied and pasted to a new file and the channels tab will show only a gray channel.  The post-production is user determined where the transition to b & w is algorithm based - I'm not certain but I think that the channel deletions produce ortho rather than panchromatic "paper" as clouds do not appear in the Iron Duke picture.  Mikkel's sky is post-production in the original (I think).  I haven't tried this out in DarkTable as I don't yet have much experience of it.  What is clear, I think, is that all the colurs are rendered only on the basis of their original tonal quantity/quality when tint is no longer a permitted parameter.

 

The dark buffer beam does suggest an orthographic rendition of the reds, although if you are selecting blue channel only, does that mean it is more like the even earlier blue sensitive bromide films?

 

I've amended my initial post due to usage of bad terminology, I'm not using filters, I'm using adjustment layers.

 

 

The numbered layers are the pictures I pasted in that get processed by the upper layers.

 

I'll pop your colour chart into my template to see what results that gives.

[57xx]

1 hour ago, kitpw said:

A few further experiments in monochrome....

The grey chart is the same colour chart rendered into b & w in the same way

as the Iron Duke picture above.

 

Just to illustrate how greys (or is it grays?) are influenced by what's around them. 

All the larger grey squares are the same square repeated in different parts of the grid.

(There's a small light grey square crept in...don't know where that came from).

Although the're the same grey square, they look darker or lighter depending

on where they are on the grid.

 

I think your chart there is showing quite a bit of "red sensitivity", so not orthochromatic. The reds on the 2nd row should be coming out very dark.

[kitpw]

17 minutes ago, 57xx said:

blue sensitive bromide films

...not sure!  That's the problem of relying on algorithms. I did the colour chart to see if that would confirm what it's actually doing, one way or another.  As you pointed out, the red buffer beam has rendered very dark where the reds in the chart are light grey - both by the same method which confuses things a bit.

 

17 minutes ago, 57xx said:

I'll pop your colour chart into my template to see what results that gives.

That'll be interesting - I think your latest post just arrived as I was about to send this so I'll press 'submit reply' anyway.

 

 

[57xx]

Here's the results.

 

Ortho:

 

Pan:

Edited August 5, 2023 by 57xx

[kitpw]

Ortho, 2nd row, third from left tells the story - it's really dark which is as it should be, it's the strongest "true red" (to my eye!).  The "pan" chart is a scale of greys which again is as it should be, so full marks on both! 

 

I must look again at why the buffer beam should come out properly dark using the channels approach; also the red wagon in the goods yard at Farthing is darker than the grey wagon - both are what I expected. I'll have a look at the Photoshop comment/help area and see if that turns up anything.

 

 

 

[magmouse]

Kit, there seems to be something odd about the colour charts you posted. On the grey chart, row 5, the second square in is almost black. It corresponds to a medium blue, which I would expect to be very pale or white with ortho film, or when just using the blue channel. As you note, the reds in the chart are very light, so we are seeing pretty much the opposite of what we should be getting. Has a simple inversion taken place by mistake?

 

I’ve also been thinking about this approach of using the blue channel as the basis for the black and white conversion. As a general principle it makes sense, but it assumes the spectral response of the blue channel produced by the camera is the same as the spectral response of ortho film. We don’t really know how reasonable that assumption is. Equally, we don’t have all that much else to go on, unless we can get some data on the spectral response of ortho film.

 

Nick.

[57xx]

49 minutes ago, magmouse said:

Equally, we don’t have all that much else to go on, unless we can get some data on the spectral response of ortho film.

 

Ask and yea shall receive....

 

 

This is for Ilford Ortho Plus 80, a modern ortho film.

[kitpw]

8 hours ago, magmouse said:

Has a simple inversion taken place by mistake?

Very likely, although it doesn't explain why the Iron Duke buffer beam is dark.

However, by a slightly different method, the blue channel only produces this:

which is I think "corrected" in that the colours with a red component (buffer beam)

are now going towards black where the lighter blues (sky) are going towards white.

[57xx]

6 hours ago, kitpw said:

Very likely, although it doesn't explain why the Iron Duke buffer beam is dark.

However, by a slightly different method, the blue channel only produces this:

which is I think "corrected" in that the colours with a red component (buffer beam)

are now going towards black where the lighter blues (sky) are going towards white.

 

That looks better. For ortho film I'd expect the greens to be lighter too, so I do think this is probably a better representation  of pre-ortho bromide emulsions.

[wagonman]

On 03/08/2023 at 22:45, 57xx said:

With added film grain and taken the edge off the focus.

 

Given that most photographers were using large format plates I doubt 'grain' would have been an issue. Nor indeed would focus – a least for a static subject like this. By the turn of the century optical design had reached a high degree of sophistication with only coating and the use of aspherical elements yet to come, plus the use of computers for the number crunching (in the 1840s Petzval had to call on the Austrian army for that job).

[57xx]

I've done a quick visualisation to help with the spectral response of the Ortho 80 graph posted before.

 

 

 

The weird transition to purple/violet is because most colour gradients only extend to the visual spectrum and abruptly stop at 400nm, this one was one the few that extended a bit past it. My addition is basically going in to UV.

Edited August 7, 2023 by 57xx

[kitpw]

These articles are of interest if a little on the long side:

https://cmykhistory.com/orthochromatic-photography-part-1/
https://cmykhistory.com/orthochromatic-photography-part-2/

 

One passage in particular caught my attention (from part 1). "The only method for reducing the amount of blue light reaching the plate was to either modify the illuminating source, or to filter the light at the camera before it reached the negative, using a yellow or orange screen. The use of yellow screens dates back as far as 1858, when William Crookes discovered that a yellow filter placed in front of the camera lens gave a better rendering of color values in reproductions of paintings on gelatino-bromide plates. Screens became a necessary component of the orthochromatic process. Reducing blue light reaching the plate helped emphasize the effect of the sensitizing dyes. While there was no increase in the green or red light, increased sensitivity of orthochromatic plates to those colors, coupled with the reduction in blue light, created a more uniform spectral sensitivity."

 

[57xx]

I had read about use of yellow filters on some other sites.

 

Another link for some lengthy reading:

https://www.35mmc.com/02/05/2023/spectral-sensitivity-of-bw-film-a-deep-dive-into-orthochromatic-panchromatic-and-all-the-rest/

 

I have read it all through yet, but jsut skimming down and looking at the pics already reveals a lot of information, especially the renderings of their test target.

[57xx]

On 08/08/2023 at 17:36, kitpw said:

These articles are of interest if a little on the long side:

https://cmykhistory.com/orthochromatic-photography-part-1/
https://cmykhistory.com/orthochromatic-photography-part-2/

 

One passage in particular caught my attention (from part 1). "The only method for reducing the amount of blue light reaching the plate was to either modify the illuminating source, or to filter the light at the camera before it reached the negative, using a yellow or orange screen. The use of yellow screens dates back as far as 1858, when William Crookes discovered that a yellow filter placed in front of the camera lens gave a better rendering of color values in reproductions of paintings on gelatino-bromide plates. Screens became a necessary component of the orthochromatic process. Reducing blue light reaching the plate helped emphasize the effect of the sensitizing dyes. While there was no increase in the green or red light, increased sensitivity of orthochromatic plates to those colors, coupled with the reduction in blue light, created a more uniform spectral sensitivity."

 

 

Some interesting paragraphs relating to @magmouse Nick's observations on old photos earlier in the thread:

Quote

George Hindlesham wrote that orthochromatic plates do help to differentiate clouds from the blue sky. “By the use of an orthochromatic plate, exposed behind a suitable color filter, it is very often possible to obtain natural clouds in landscapes if a little care is taken in judicious development.”20 However, one disadvantage was in the rendering of haze, “when the distance is desired to show but very faintly, in order to give atmosphere to the photograph. As this is generally of more or less bluish tint, the screen used for the foreground will sometimes bring the distance a little more forward than it should.” Sanger Shepherd also felt that distance should be rendered as the eye sees it. “The reflected white light is one of the great charms of landscape, for without it we have no impression of distance or atmosphere, so that for this purpose at least I do not think we should try for complete correction.”11

 Interestingly, haze in landscapes could also be reduced using a polarizing filter, a common technique in modern photography. Polarization was available in 1898, but its use would have been questioned by photographers who wanted to retain haze in their photographs. As a compromise, a light yellow screen, not completely opaque to blue light, could help with the use of orthochromatic plates while retaining some of the haze.11 

Unlike Hindlesham and Shepherd, Acworth felt that ordinary plates, not orthochromatic, exaggerated the haze in landscape photography, making the image appear foggier.16

 Cramer also argued that the reduction of haze by orthochromatic plates gave separation between white clouds and blue sky. Clouds and sky tend to blend together due to the blue sky giving the greatest exposure on regular plates. The same was true for seascapes, where separation between the water and sky was essential. Burton felt hazy distances were better rendered using orthochromatic plates, which gave better differentiation between clouds and sky, and snow-covered peaks and the sky.3 Sunsets and autumn landscapes also benefit from orthochromatic plates sensitive to orange and red.9 

 

[Compound2632]

Interesting stuff there but would it have been of any relevance or interest to, say, the Gloucester Wagon Co's staff photographer?

[57xx]

Reworking the hue/saturation adjustment layer to match the Ortho 80 test target on the link I posted earlier results in some changes that bring together some details of research that did not sit right with my previous attempts using the parrots as a guide. I don't think the rendition of orthochromatic greys was accurate on that image. I've now got the lighter blues and less yellow response, as would be expected from the texts I've been reading. I've also been able to tweak things using the distinctive S curve for contrast. As I originally posted, I found a lot of contradictory information, but things seem to be converging on more solid info.

 

 

Revised using Ortho 80 target:

[57xx]

38 minutes ago, Compound2632 said:

Interesting stuff there but would it have been of any relevance or interest to, say, the Gloucester Wagon Co's staff photographer?

 

Certainly not a lot where the haze is concerned, but better rendition of "colours"? Probably.