Physics and chemistry of pinhole photography

P H YSICS AND CHE MI ST RY OF PINH OL E P HOTO G R AP HY

CONTENTS CHAPTER 1 MAKING THE CAMERA CHAPTER 2 PREPARING THE PHOTOGRAPHIC MATERIAL CHAPTER 3 CAPTURING THE IMAGE CHAPTER 4 DEVELOPING THE IMAGE CHAPTER 4 RESULTS

CHAPTER 1 MAKING THE CAMERA

Camera - Cardboard - Tin foil - Black paper - Concave & Convex lens

Tools - Glue and black tape - Needle - Pen / pencil - Scissors / knife

Photo paper taped to back of box

Box interior covered with black paper

Foil pricked with needle and taped to front of box

Aperture cover

SINGLE PINHOLE CAMERA

Photo paper taped to back of box

Box interior covered with black paper

Foil slit with needle and taped to front of box

Aperture cover

SINGLE SLIT CAMERA

Photo paper taped to back of box

Box interior covered with black paper

Slats

Foil pricked with needle and taped to front of box

Aperture cover

MULTI-PINHOLE CAMERA

Lid

Photo paper taped to the back

Aperture with cover

PARABOLIC-SURFACE SINGLE PINHOLE CAMERA

Box cover

Reel of photo paper in the middle of the box

Box interior covered with black paper

6 pieces of foil pricked with needle, taped around box

PANAROMIC PINHOLE CAMERA

DLSR lens replaced with pinhole cover, use shutter speed to control brightness of image

DIGITAL PINHOLE CAMERA

CHAPTER 2 PREPARING THE PHOTOGRAPHIC MATERIAL

Binder & Chemicals - Gelatin as binder on non-porous materials - Fotospeed emulsion

Materials Ready-made papers : - Ilford multigrade resin-coated b&w paper - Harman direct positive paper - Fomaspeed paper Other materials (to be coated) : - Timber - Plastic - Glass - Cloth/canvas - Aluminium can - Plaster, stone and concrete blocks

Porous materials : Timber Cloth/canvas Paper Stone block

Porous materials do not need binder

Non-porous materials : Plastic Glass Aluminium sheet Plaster/concrete block Apply gelatin binder to non-porous materials for photographic chemicals to adhere

Soften photo emulsion in hot water bath for at least 20 minutes

Under safelight, mix photo emulsion and water [1:2]

Photo emulsion Gelatin Non porous material Porous material

Using a foam brush, apply uniform coating of photo emulsion on materials.

Leave coated material to dry for at least 12 hours in the dark, before putting it in the camera.

CHAPTER 3 CAPTURING THE IMAGE

Photographic Material [Sensitivity / Iso of paper]

Focal length Exposure time [Duration aperture is exposed to light Exposure

ISO

Aperture size

Focal length [Distance between pinhole and photographic material Aperture size [Size of pinhole]

1

3

2 1

In safelight, attach coated material or ready-made photographic paper to the back of camera.

2

Position camera away from direct sunlight. Lift camera aperture cover to expose.

3

Cover pinhole to end exposure. Bring camera to darkroom for developing.

Refer to photography album to see prints.

VARIABLES FOCAL LENGTH

LIGHT CONDITION

focal length (mm)

50

100

Optimum exposure times

150

angle of view

SUNNY

OVERCAST

CLOUDY

INDOOR

NIGHT

5-10s

10-15s

15-20s

30m-1hr

FEW HOURS

PAPER SENSITIVITY Paper brand

magnification

Fomaspeed

ISO speed APERTURE

f-stop amount of light depth of field/focus

4

Ilford RC 3

Harman 1

Exposure time to produce equal image quality f/1.4

f/2

f/4

f/8

f/16 DISTORTION WITH LENS Without lens Image is blurry

EXPOSURE TIME

With converging lens Image is more focused & sharper

duration of exposure brightness/ sharpness of image

With diverging lens Light diverges, no image formed

CHAPTER 4 DEVELOPING THE IMAGE

Chemicals - Ilford Multigrade developer - Ilford Ilfostop - Ilford Rapid Fixer

Work in darkroom with safelight and ventilation.

Mix developing chemical (A) and water [1:9]

Pour mix into tray A

Mix stop bath (B) and water [1:19]

Pour mix into tray B

Mix fixer (C) and water [1:9]

Pour mix into tray C

Remove exposed material from camera and immerse it in tray A for 3 minutes to develop

Remove from tray A

Immerse in tray B for 2 minutes to halt developing

Remove from tray B

Immerse in tray C for 3 minutes to fix image

Wash under running tap water for 30 seconds to remove chemical residue

Hang to dry

CHAPTER 5 RESULTS - DUNGENESS PHOTOGRAPHS - TEST PRINTS

Focal Length of camera : 10cm Exposure time : 10-15 seconds Sunny weather

Pinhole photographs taken in Dungeness

Single pinhole photograph of the power station

Multi pinhole photograph of the power station

Single pinhole photograph of a derelict hut

Multi pinhole photograph of a derelict hut

Constants : Emulsion - Silver nitrate Focal length of camera - 10cm Type of camera - Single pinhole Exposure time - 15 seconds

Rusted metal

Pinhole photographs tests on various materials

Aluminium Plaster

Tracing paper

Canvas cloth

Plastic

Timber

Watercolor paper

Ceramic

Glass