How do I remove the exposed 4x5 or 8x10 film and put new film in ?
It is practically essential to use several film holders, not just a single one.
So, when a film is exposed, you store the holder apart, and you take another holder containing an unexposed film.
Loading the holders
A film box consists of 3 half-boxes nested together, and it is light tight. Everything you will do with the film must be done in the dark.
The film holders must always be loaded and unloaded in the dark : either in a darkroom, or in a changing tent or changing bag.
When you load the film, you take it out of the film box, and insert it in an empty holder.
After the film is loaded, you close the holder by means of the dark slide, which is a kind of lid, that closes hermetically the holder.
Manipulating the holder before and after the exposition
<ul>
<li>When you place the holder in the camera, before exposing the film, you remove the dark slide.
<li>After the film is exposed, you close again the holder by inserting the dark slide.
<li>Then you identify this holder as being exposed.
You'll notice that a dark slide has generally two colors : one side is white, and the opposite side is black. You can use these colors to identify an exposed holder from a non-exposed one.
<li>When the holder is closed with the dark slide, it is again light tight, and you can remove it from your camera and place it in your bag.
<li>Preferably, do not mix exposed and non-exposed holders, and store exposed holders in another place in your bag, to avoid exposing again a sheet film which has been already exposed.
</ul>
What do I do with the exposed film sheet ?
First, find one or several empty film boxes. (Ask for them in the store where you buy your sheet films, or in a laboratory, they always have plenty of them).
In the darkroom, or in a changing tent, open your holders, remove the exposed film and place it in this empty film box. That's all.
Of course, if you use only one holder, you must unload the film in the dark, place it in this box, and load your holder again.
As the price of a holder is rather unexpensive (considering the price of all your gear), it would be silly not to buy several ones.
The Quickload
The Quickload and Readyload are plastic holders, which use individually-sealed sheets of 4x5" film, in the same manner than Polaroids in 545 sheet-film or 550 pack-film holders. The sheet-films are sealed individually in a light-proof and dust-proof envelope.
Quickload is a trade mark by Fujifilm, and Readyload is a trade mark by Kodak.
These special holders do not need to be loaded and unloaded in the dark. When they are inserted in the holders, you do it in the daylight.
The holder is inserted in the camera as an ordinary holder, and a part of the envelope containing the sheet-film is used as a dark slide.
(Of course, the Quickload or Readyload sheet-films must be unloaded in the dark for development).
Advantages :
<ul>
<li>You do not need to load/unload the film in the dark,
<li>The films are dustproof,
<li>To some extent the holders are dustproof too, as the Quickload holders are provided with a cap. You need nevertheless to be careful about dust.
<li>Very good film flatness (Pressure plate)
<li>You need only one holder, for traditional films you need several ones.
<li>When using traditional holders, pre-loaded in the dark, you can't change the emulsion, (B/W, color, transparencies) or the speed of films (100/400 ASA) if you have to. With a Quickload or Readyload, you can change the kind of film each time you need.
</ul>
Drawbacks :
<ul>
<li>Less emulsions are available, either with Fuji or with Kodak,
<li>Only in 4x5" format,
<li>No 5x7" or 8x10" holders and films available.
<li>Individually-sealed sheets of 4x5" film are more expensive (about twice the price of an ordinary film box),
<li>The holders are rather expensive too, (But a single one is enough)
<li>The weight of a holder and a box of 20 sheet films in Quickload or Readyloads is heavier that 10 Fidelity 4x5" pre-loaded holders.
</ul>
Operating mode :
<ul>
<li>You can preload the holder, or load it after it has been placed on the camera,
<li>Place the holder in the camera : either you slide it in the camera, or you remove the groundglass and fix the holder with the Graflok attachment,
<li>Remove the cap,
<li>(If not preloaded) Insert the Quickload envelope in the holder : it is securely locked in the holder by means of a metal clip,
<li>Pull out the envelope (like a dark slide : only a part of the envelope moves out, the film is held by the clip),
<li>Take the picture,
<li>Push the envelope fully in again as a dark slide,
<li>Unlock the button, pull out the whole Quickload envelope ,
<li>Seal the envelope with an "Exposed" sticker, (20 stickers come with the film box) to avoid light leaks, and to identify the film as exposed.
</ul>
Last, but not least, never mix different emulsions and holders : sometimes, people use a Polaroid holder with Fuji films, or a Kodak film in Quickload holders, or a Fuji film in Readyload holders.
Physically, it is possible, as the sheet film can always be inserted in the holder. But the results are sometimes very poor ones : Polaroid holders do not have a pressure plate, and film flatness with Fuji or Kodak films is bad, and using Fuji films in Quickload holders (or opposite) may cause light leaks.
Sorry to be so long, but I hope this will help you.