Build Your Own Home Darkroom Pdf
Introduction
Build Your Own Computer. Machine than if you simply do it at home for your personal use. The decision is yours. Are you simply looking for a machine to do some basic word processing, maybe some home finances on, read your email and surf the web? Then we can get a pretty. How to Build a Home Bouldering Wall. There is no more effective way to improve at rock climbing than to have your own home bouldering wall. A wall simulates the demands of rock climbing better than any other form of training, plus it lets you work on technique while you're getting stronger. Bouldering is a fantastic full-body work.
There's no reason to defend one medium against the other, both have their virtues and drawbacks, but the preparations to build your own darkroom and to develop your films and create prints will give not only be an adventure in terms of knowledge, it will be a rewarding and fun activity that may reveal new horizons in your own photography.
The electronic temperature controller units which are commonly available in the market are usually quite sophisticated in design and therefore costly. These are more suitable in areas where a precise temperature control may be required. Obviously such hi-end types of control systems may be of no help or too expensive to many electronic hobbyists and in places where the needs are not that specific or critical. Also the cheap types are not reliable at all, because their accuracy is not consistent. The diy temperature controller circuit presented in this article is super simple in design, yet is able to produce reasonably accurate and consistent temperature control over a range of 40 to 125 degrees Celsius, which is fully adjustable.
How Does the Circuit Functions
Every electronic semiconductor component has got a “bad nature' of changing its characteristics in the influence of a varying ambient temperature.
We have studied in one of my previous articles how it becomes important to optimize the current through a zener diode due to the effect of a varying ambient temperature so that its value can be kept constant.
But this particular “bad behavior' of semiconductors has been perfectly exploited in this electronic temperature controller circuit.
Here the diode 1N4148 is used as a reference to monitor the ambient temperature whereas the transistor
BC557 is configured as a sensor to sense the temperature in question with reference to the ambient temperature.
Home Darkroom Kit
In the influence of the applied heat, the base emitter voltage of the transistor will drop. The drop of voltage will be around 2mV for one degree of rise in temperature.
Due to this the transistor will gradually start conducting and at a point (as per the setting of P1) will switch ON T2 to activate the relay and the external cooling agent.
Construction Hints
The construction part is very simple as the circuit of this low cost temperature controller requires hardly any components. The procured parts may be simply inserted into a small piece of general purpose PCB and soldered to interconnect their leads.
The whole assembly can be housed inside a sturdy plastic enclosure, allowing only the mains cord and the sensor out of the box. The length of the sensor wire should not be more than a meter long to avoid stray signal pick-ups.
The potentiometer should be fixed over the box so that it can be adjusted externally to set the tripping point as per the applications.
Setting Up the Unit
For setting the unit you will require a digital temperature meter, and may be done through the following simple steps:
- Plug in the unit to the AC supply; connect its sensor as well as the sensor of the meter to the heating element whose temperature is required to be controlled. Also, connect the heater to the output of the unit, so that now it starts heating up.
- Monitor the rise in temperature over the digital meter, as soon as it reaches the required tripping point, adjust the potentiometer so that the relay just activates and breaks the supply to the heater.
- Consequently, the heating element will start cooling down and after a certain period of time its temperature will come down to a level where the relay will restore back the supply to the heating element and the cycle will repeat. This time period will depend upon the hysteresis of the circuit.
Applications
The simple circuit of this low cost temperature controller may be used for the following couple of important applications:
To Protect Power Transistors: In many electronic circuits power transistors perform vital functions of controlling heavy output loads and therefore may get heated up to appreciable limits. Though these are always fitted over aluminum heat sinks for optimum cooling, the temperature at times may cross uncontrollable levels.
The sensor of the present circuit can be integrated to the heat sink and the relay contacts may be wired either to a cooling fan or may be simply used to switch OFF the power so that the heat may not exceed to a damaging limit.
In Poultry Farms: The newly hatched chickens inside poultry farms are very vulnerable to the changing climatic conditions. A proper regulation of the temperature around them thus becomes very essential. Usually hi-power incandescent bulbs are used to keep the inside atmosphere of the poultry farm warm and conducive to the baby chickens, but if the intensity of these bulbs are not controlled, things can get hazardous.
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Again, by attaching the sensor of the proposed electronic temperature controller circuit to a particular bulb may be effectively used to switch them OFF in case the ambient temperature rises to a critical point thus helping to keep the average farm temperature to a healthy proportion.
Readers may customize and modify this diy temperature controller circuit as per their own needs and specifications to find its numerous other applications. Just remember to keep the reference diode far away from the temperature which is to be sensed.
Build Your Own Home Kits
So digital photography, with its glitzy, complicated cameras and hours spent getting RSI on your computer, is not for you. You prefer to use a film camera and even like the idea of beavering away in a nice warm darkroom on a summer's afternoon - indulging in a bit of visual alchemy to the accompaniment of Test Match Special or The Afternoon Play.
Building a home darkroom is quite possible but, before you get too carried away, don't bother with home wet printing unless you have the space to create a 'proper' darkroom. The chemicals are smelly and a dodgy old enlarger balanced precariously on the edge of your bath is bound to end in disaster. Any attempt to produce photographs in your bathroom or kitchen is sure to end in domestic disharmony and, if you don't have the space (or the cash) to set up your own darkroom, you could always hire one by the hour at www.ilfordphoto.com/photocommunity/darkroom.asp
The other caveat I'd add is that it isn't worth wet colour printing at home, as this involves complicated coloured-light filtration and extremely expensive materials. Digital printing is the best method of producing colour images. However, if you ask me, a black-and-white bromide paper print is still superior to its digital equivalent. The blacks are deeper, the feel of the paper is nicer, and it's a hand-crafted product.
To create a darkroom suitable for black-and-white printing, you'll need a dust-free spare room with access to running water and a drain. Alternatively, clear a space in the garage (you know it's full of junk anyway). A couple of partition walls at the end will make a sturdy darkroom with a floor that will forgive any spillages. There's probably a garden tap nearby, too.
Once the darkroom is fully stocked, but before you actually start developing, I'd recommend you practise with an old strip of film and the lights on. Then, when you come to do it in the dark (total darkness, remember), hopefully you won't be all fingers and thumbs. If you're feeling confident, try practising with your eyes closed before you risk anything with a real roll of film.
A tip, also, about loading your film on to the plastic spiral or reel: make sure the reel is completely dry before you attempt to load the film. Any moisture and it will swell and jam. And now, finally, you're ready to begin developing.
Be extra careful with the temperature of the developer. An increase of just a couple of degrees and you will have 'pushed' your film (increased its ISO) and your photograph will be overexposed.
When printing, keep variables to a minimum. The developer should be kept at a fairly constant temperature (around 20C) and the exposure time on the enlarger kept at, say, 10 seconds. And develop the prints for the same time (two minutes is about right). By keeping the timing and temperature constant, the only variable will be the iris on the enlarger lens, which will make adjustments to your prints much easier.
Make sure you fully develop the prints to ensure you have strong black tones - if the print develops too quickly, it will produce a tonally flat image. When starting out, most people produce flat prints that lack contrast. To compensate for this, try using a harder paper: the higher the number, the more contrast the paper will give you.
Finally, you may find the chemicals affect your skin - if so, it's better to wear thin surgical gloves than use barrier cream, in case you smudge your prints. And wear old clothes! Developer stains things brown including, in my case, a lovingly hand-knitted Fair Isle jumper. You can always tell a photographic printer by their brown fingernails. Nice ...
You will need...
· Space (about 2.5m x 2m) with a designated 'wet' and 'dry' area. Your enlarger will be on the 'dry' side; a sink with running water on the 'wet' side. A long shallow photographic sink is ideal.
· You don't need hot water. A kettle will do.
· A simple, sturdy enlarger with a good lens. Don't buy one with a colour head.
· A darkroom easel to hold the paper flat under the enlarger (you need to keep the paper flat for sharp prints).
· A developing tank and reels for developing film.
· Three developing dishes: rectangular washing-up bowls do as well if not better, because the chemicals won't splash as much.
· Chemicals: specifically, film developer (D), stop bath (S), fixer (F) and wash (W).
· A thermometer for checking the temperature of these chemicals.
· A timer. The enlarger may come supplied with one, but you will need one for timing development.
· As for that 'relaxing lighting', forget dark red lights. You can't see by those and, when loading film for development, you'll need total darkness. Get lights with amber filters. The room can be reasonably light as long the light is filtered.
· You'll need a drying device for negatives and prints. You could buy a purpose-built drying cabinet; I use an old locker with a cheap fan-heater wedged in the bottom.
· As for drying prints, a scissor-type squeegee will get most of the water droplets off, then you can leave them to dry in the air.
· Some storage for your negatives, and a couple of shelves for your chemicals and paper.
For a step-by-step guide to developing and printing in black and white, go to www.ilfordphoto.com/applications/page.asp?n=9