Introduction to Traditional Plate Camera Photography

Plate/ DDS comparison

2007-04-05T18:57:47Z

Plate DDS comparison

Show time.
A roll of 120 format film has been included for scale measurement & comparison.
On the left is a standard half-plate double dark slide [DDS].
Its smaller axis dimension (the most important) measures 150mm.

On the right, is a British standard whole plate double dark slide. This measures 195mm.

The Double Dark Slide [Half-Plate DDS]

2007-04-05T18:49:57Z

Half-plate DDS

So what have we here?
This is a Double Dark Slide Film Holder [DDS for short]. It is a later development from the book form holder.
It's smaller axis dimensions here is identical to the British Gandolfi Bookform Plate Holder: 150mm.

This is very important, since with a little modification, these DDSs can fit into a half-plate camera like a Gandolfi, but NOT a Thornton Pickard half-plate camera.

These DDS are made by Kodak and labelled "For 4 3/4 x 6 1/2 inch plates".

There are similar 5"x7" DDS slides which have different axis measurements and are not half-plate compatible, particularly with modified half-plate cameras.
From the top left: a blank sheet representing the area of the half-plate film. On the top right is a closed DDS. On the bottom left is a withdrawn slide from a DDS and on the bottom right, is the exposed area of the DDS where the film will be positioned.

Bookform Plate Holder (Half-Plate)

2007-04-05T18:38:56Z

This is it.

From the top, the plate holder now has its sheet of glass inserted.

As film is expensive, I've not loaded a sheet since this would be wasted. Also, it would cover the glass.

From the viewer's plane towards the back of the image, here are the layers as a cross-section:

1. Plate-holder Sheath (removed for exposure)
2. Film sheet (emulsion facing viewer and/or the lens)
3. Glass sheet
4. Metal septum (with two prongs)
5. Glass sheet (rear)
6. Film sheet (rear)
7. Plate-holder sheath (closed in this image).

The sheath has been withdrawn and folded over and the tint of the glass can be seen against the tungsten (yellow/orange) light.

The quarter plate mask here has been taken out and placed on top of the half-plate box of film. The area of black of the mask represents the dimensions of the half-plate film and the aperture area represents quarter plate.

Lights off

2007-04-03T23:34:38Z

Lights off

The next step - loading the film into the dry plate holder - needs to be done in the dark.

Of course you knew that.

Bookform Plate Holder [Half-Plate] adapted for film

2007-04-03T23:27:45Z

Now things are coming together:

1. Book Form Plate/Film Holder
2. 2mm cut-glass (deburred edges)
3. Half-plate film [118mm x 163mm]

Efke PL25M film, also known as Efke 25 is also known as Adox 25 after a rebranding exercise. It's one of the late great vintage high silver single layer films manufactured from Croatia and is available in half-plate size [April 2007].

The plate holder has been unsheathed for demonstration purposes only. The exposed black area is where the film fits in. Behind the film fits the sheet of glass which can be seen overlaying the film box.

Bookform Holder [Half-Plate] unsheathed

2007-04-03T23:16:25Z

Bookform exposed II
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Here we have the half-plate book form holder with a sheath withdrawn to its furthest reach. There is a self-limiting stop for the sheath and it can not be withdrawn any further, hence no force should be applied.

The holder on the top is fully closed. The holder on the bottom is unsheathed and unclasped.

The position of this holder is for demonstration only - the holder should never require the clasps and the sheaths to be removed simultaneously.

Summary:

1. The clasps are unclasped for loading and unloading film/plates.
2. The sheaths are used sequentially (front side then rear side) for exposures.
3. Any time the clasps and the sheaths are raised, an error in operation will result.

Simple :)

Glass Plates II (half-plate: 4 3/4 x 6 1/2 inch)

2007-04-02T00:15:53Z

Cut glass II
Originally uploaded by plate_camera_photography.

Notice the smooth deburred edges.
The glass can be cut using plain 2mm picture glass using a glass-knife/scorer and ruler.
Deburring of the glass edges can be used with a limestone knife sharpener. The reflectance of the glass plates does not matter if these plates are to be used as sheet film pressure plates. However if these are to be used for liquid emulsion or for collodion type negatives, then it is imperative that the glass is cleaned down with isopropyl ethanol to remove grease stains from handling which might otherwise cause the emulsion to lift from the plate or fail to adhere completely.

Bookform Holders: Glass Plates

2007-04-02T00:11:09Z

Cut Glass

It would be highly unusual to find any glass plate within a bookform holder. Most of the used book form holders a photographer ever comes across will be void of internal glass plate.
Why does this matter?
Inside the book form holder is a blackened divider (see image below) which holds two pressure prongs. These prongs apply pressure against the plate in order to attain a flat level surface. If film is placed directly onto these prongs, the film will be scratched and the film surface will become warped.
Therefore a card cut-out, plastic sheet or glass plate can be inserted so that the same functional effect of a glass plate can be obtained.
I choose to use glass plates for several reasons, including the reduction of dust and debris. One day I hope to coat my own glass plates with liquid emulsion.
These glass plates were cut down to size. For half-plate film, these plates must be: 118mm x 163mm. The margins must be burred otherwise the glass will present sharp edges and hazards to skin during loading in the dark.

Bookform Plate Holder (Half-plate) open

2007-03-31T02:18:21Z

Bookform Holder Open

On the top, the bookform plate holder is closed.
On the bottom, the bookform plate holder has had its brass side-clasps unfastened and has not been opened and rotated 90 degrees.
Observe the following:

1. On both sides of the middle dividing plate are black areas
2. These black areas are the reverse side of the removable holders
3. Therefore these black areas represent the actual area of exposure
4. The black areas are also hinged with black cloth tape
5. This enables the holder cover to be flexed when withdrawn
6. The middle dividing plate acts as an internal darkslide to prevent fogging of the complementary negative.
7. The dividing plate holds two prongs which exert pressure against the plate.

However this is not all. A half-plate holder holds more. The current open position is primed to accept glass plates only. Users of glass plates place the emulsion side towards the hinged cover; fold over the middle divider, and carefully lock this before proceeding to do likewise with the contralateral side. The technique for loading film requires very little modification using the same principles.

Bookform Plate Holder (Half-Plate) clasps

2007-03-31T02:05:56Z

Bookform clasps
Originally uploaded by plate_camera_photography.

The first step towards opening the bookform plate holder involves lifting the brass side-hinges as shown in the holder on the right.
This enables the bookform holder to split open from top to bottom. This is the position required for:

a) loading a plate or film into the holder
b) extracting a plate or film for processing post-exposure

In contrast, the bookform holder on the left is sealed and can not be opened. This is the standard position during carriage; pre-exposure and post-exposure.
More on the position of the holder during exposure later.

Bookform Holders Comparison

2007-03-31T01:32:13Z

Bookform Holders Comparison
Originally uploaded by plate_camera_photography.

The traditional folding plate holder for half-plate camera.

At first glance, both holders look like similar blocks of wood. The mahogany wood is carefully selected and cut in position; carefully placed and glued in a specific pattern. Notice the panel grain runing across the main panels, and how the panels divide, enabling the front holder to fold above and over the body of the plate holder.
The plate holder on the left is a standard Gandolfi fit holder. It measures 154mm from side-to-side.
The standard English half-plate bookform holders are 154mm wide measured flange to flange. The flange lips are approximately 2mm wide each, rendering the wall to wall width (i.e. planed off flanges) 150mm.
This is the same distance as the space in a Gandolfi half-plate film back. Therefore any half-plate camera with a 150mm width space section will be rendered compatible.
On the right is a Thornton Pickard half-plate holder. Thornton Pickard bookform holders are 148mm wide measured flange to flange. Excluding the flanges, from wall to wall, its width is approximately 144mm. This falls significantly short of the 150mm required space to sit flush in a Gandolfi camera. Archives indicate that these were used with early Thornton Pickard cameras (Imperial, Triple Extension types) spanning 1890 - 1925 and are therefore later designs than the Gandolfi type holders..
Both holders take up the same thickness.

Traditional half-plate lens

2007-03-26T03:19:44Z

Traditional half-plate lens
Originally uploaded by plate_camera_photography.

The Gandolfi camera arrived with no lens and an ill-fitting mahogany lensboard. A few years ago, I acquired a Taylor Hobson Series III Cooke lens in anticipation of this project. This is a legendary lens (over a century old too!) made of brass & English glass. The designation on the lens led me curious over plate cameras: stated for use is the inscription: "4 3/4 x 6 1/2 inch plates" with a focal length of 7.7 inches. Each lens from the factory was subject to tolerance tests, so I gather that other variations of similar focal lengths exist (more on this later). Diminutive in size, this Series III lens even has the seller's name engraved by the lens manufacturer. Seems like this was a common occurrence before global marketing made everything available on the internet. In any case, there isn't much information about the lens apart from the Taylor & Hobson website which makes some reference to Series III lenses. The lens is an uncoated lens (as all lenses of the era was) so I've added a custom fitted lenshood which really looks the part. Lens measures just under 3 cm from the lens panel making it highly compact and portable for landscape work.

Taylor Hobson Series III Cooke Lens
Focal Length: 7.7 inches, f 6.5
Fitted with a custom lenshood.

This is the successor to the radical Taylor Hobson Triplet of the 1890's which covers 5"x4" format, but not half-plate format completely. From the Cooke Optics website:
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The Cooke Triplet concept was a simple and elegant solution to design issues that plagued lens designers of the era.

Dennis Taylor was understandably excited about his development, and on 7th September, 1893 wrote a letter to Taylor, Taylor & Hobson, enclosing a photo of York Minster taken with "a trial lens constructed on my new principle, having a equivalent focal length of 7 1/4 inches. The exposure was made on an Edward’s Landscape Plate (Slow) and with a stop equal to F/7.7 (by careful measurement)."

He goes on to say: " You will see that the Minster wants a decidedly wide angle to get it all in, consequently I had to raise the rising front by 1 1/2 inches so that the lens is tried more severely than if used centrally opposite a 7 1/2 x 5 plate which size it is manufactured for. On submitting this print (or rather the negative) to an experienced amateur photographer, after looking carefully at it and without my asking, he said that if he had been using a 7 1/4 Ross Portable Symmetrical or other lens of such type, he would not expect to get so good a result without having to stop down to F/32, a conclusion which I had myself independently arrived at."

Having no desire to enter the photographic lens business, T. Cooke & Sons offered the manufacturing rights to Taylor, Taylor & Hobson of Leicester, optical instrument makers who had a reputation for producing quality optical products since 1886 when William Taylor founded the company in Leicester with his brother, Thomas Smithies Taylor. William Taylor's philosophy: "Don't do what everyone else can do; go out for something new," coined in 1886 holds true at Cooke Optics today.

The first Cooke photographic lens was made by TT&H in 1894 based on Dennis Taylor’s Cooke Triplet patent of 1893. (There is no familial relationship amongst Dennis Taylor and brothers William and Thomas.). TT&H went on to produce subsequent lens designs by Dennis Taylor through Series V. The licensing agreement stated that the lenses would be sold under the trade name "Cooke". The very first lenses made were brass and included the inscription "H.D. Taylor's patents."

Early Cooke Triplet design lens offered critically fine definition right up to the margins of the photographic plates.

In 1895, the Cooke lens was awarded the only medal of the "Royal Photographic Society given for improvements in lenses within recent times."

The TT&H Cooke lens catalog of 1897 states:
"Lack of sharp definition at the margins, and blackness and lack of detail in the shadows, are among the commonest defects of photographs. The introduction of lenses which, without the use of stops, yield definition uniformly fine throughout their plates, marks quite a new era in photography."

Today, triplets of various kinds are used almost universally for lenses of intermediate aperture sold on smaller still cameras.

This was the beginning of a legacy of superior and innovative lens design and manufacture under the Cooke name that continued throughout the 20th century beginning with still portrait, telephoto and process lenses, through the development of acclaimed Cooke cine and television lenses, and continues today by Cooke Optics Limited, with award-winning 35mm cine prime and zoom lenses.
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