Exact Full Plate Image Dimensions?

[John Layton]

I've been getting just a bit intrigued with full plate (6.5x8.5) lately...and am thinking that it wouldn't be too much of a stretch to adapt my Zone VI series II enlarger to this format.

My Heiland LED will not quite cover, but the actual negative stage aperture is very close.

...what I need to know is the actual image dimensions. I'm assuming something like 6.25x8.25...is this close?

[RLangham]

I'd assume with the age of the format that it would vary from camera to camera. Hell, the precise dimensions of the film gate might actually vary within the same model of camera. I'm assuming you don't have an exposed plate or sheet?

[John Layton]

no...but its typical that the actual image dimensions for LF are appx. 1/4 inch less than full film dimensions, and I'm wondering if this is also true for full plate.

[Tin Can]

There has been some discussion here, and some variations

https://camerapedia.fandom.com/wiki/Plate_Sizes

Nodda Duma makes glass plates with emulsions and might have the best criteria

[paulbarden]

All references I have seen (people I know who are VERY familiar with the antique sizes) state that Whole Plate is 6.5" X 8.5", and so I expect you can be quite certain that is the exact size for a Whole Plate.

19th-Century Image Plate Sizes:

Whole Plate: 6.5 x 8.5 inches (16.5 x 21.5 cm)
Half Plate: 4.25 x 5.5 inches (11 x 14 cm)
Quarter Plate: 3.25 x 4.25 inches (8 x 11 cm)
Sixth Plate: 2.75 x 3.25 inches (7 x 8 cm)
Ninth Plate: 2 x 2.5 inches (5 x 6 cm)
Sixteenth Plate: 1.375 x 1.625 inches (3.5 x 4 cm)

[Tin Can]

https://www.pictoriographica.com/ sells ready made glass plates any size

[Tin Can]

https://cwfp.biz/platesizes.php

Read paragraph from site above, "Note that plate sizes are approximate. Besides variation in the sizes of plates as they came from the manufacturer, finished plates were often trimmed on one or more edges by the photographer to allow for positioning under the mat. Any shifting of the plate under mat from exact center - to better center or otherwise improve the composition seen through the mat opening - would normally cause one or more plate edges stick out beyond the mat, and the photographer would have to trim off these projecting portions to allow the image package to fit in a standard-sized housing."

[karl french]

Well, the film is generally 1/16th under on each dimension and the rails in the holder eat up another 1/8 or so. I have 3 different brands of whole plate holders. They all produce very slightly different sizes based on the width of the film rails and end flap.

[Nodda Duma]

Whole plate is a great format and amongst my favorite.

The whole plates I make are exactly 215 x 164mm (+0 / - 0.25mm tolerance) x 1.3mm thick. The glass is precut and so it’s very consistent.

This size works for all the antique whole plate holders out there (mine are undercut slightly so there’s no fit issues with wooden holders that may have shrunk or swollen over the decades). Antique whole plates were exactly 6.5” x 8.5”, or 165.1 mm x 215.9mm exactly. Thicknesses I’ve seen were 0.050” or, less commonly, 0.075”.

As a side note, half plate seems to have had the widest variation before it went obsolete. The dimension Paul lists above seems to have been 1 of 3 fairly common sizes. The other two half plate sizes I’ve cut for people are 113 x 164 and 108 x 164 (the dimensions I cut them to). Of the three sizes, 113 x 164 (4 1/2” x 6 1/2”) is the most common. The least common that I’ve seen, ironically, is the one that’s actually half of a whole plate: 4 1/4” x 6 1/2”.

Hope this helps!
Jason

[Sal Santamaura]

If you use a camera that takes modern holders (Ebony, Chamonix, Lotus), the defacto "standard" I worked out with Lotus, copied by Chamonix and Ebony, is that they expose an image area of 157.6 x 206.9 mm. Other older cameras / film holders, as well as glass plate holders, will differ.