WHAT'S IN A PICTURE. By Grant THOMSON 8/9. PICTURES FROM THE OCTOBER CONFERENCE 1984.

WHATS IN A PICTURE 7

Aerial photography can produce pictures with great artistic merit and aesthe· .. appeal; but more routinely, they are regar~ttci as a reliable documentary reco':: of use to Pf!Ople having specialist interests, many of which are science basec.

To meet this need tor a clear documentary record the aerial photographer wL: have to minimise the effects of atmospheric haze, vibration and movement of t aircraft in flight, these factors being coupled with very small-scale images in the negative, all of which combine to reduce image quality and therefore use-tulness of the photography.

Customarily the films used in aerial photography are processed to give hig e' contrast negatives than are normal in most pictorial applications, and the neg-atives shaded, "dodged" and "burned -in" during printing to give a pleasi ;; uniform result. Professional air-survey organisations usually contact-pri their 240mm x 240mm format roll film negatives on Milligan Electronic photoprinte-s that automatically achieve such "dodging" to a very high standard of contro_ over tone-reproduction (equivilent to unsharp masking techniques) in a matteof a few seconds exposure time.

Some applications of aerial photography and airborne electronic imageifII sys-tems call tor a yet more rigorous approach however. As an example, the rapid -expanding area of applied aerial (and satellite) photography in remote sensi ;; tor natural resources demands that the radiometric properties inherent with a scientific record such as an aerial photograph are altered as little as possible, so that the experienced interpreter can appreciate image effects that are more related to the ground, and not to be misled into attributing an apparent change in reflection to natural phenomena when in reality it is a photographic artitacthat has caused the altered tonal values, tor example, by dodging a print ·o make a "nice picture" •

There are of course many instances where skiltull handprinting with dodgi ; or the use of electronic photoprinters to enhance photography are essentia: but gradually the techniques being evolved in remote sensing are providing expe'-ience to show that the aspect of radiometric fidelity in aerial photograp., needs to be kept in mind, and that strict control over exposure, processing a printing must be exercised, especially when operating with multispectral phot()£-raphy or image radiometry linked with computers, to cite just two examples,

G.H.TH~

'9

Group summer e~hibJtion

another view of m~mbers exhibition at AVONCROFT. Thanks are due to Dr POLLITT for the organisation and the fine picture.

S. PICTURES TAKEN AT THE OCTOBER CONFERENCE.

Brian planning something good with "ILFORD"Man,Bill WISDE -

a picture by Bria,~ Tremain FRPS showing the "PERIPHERY" camera 58 ,-_

--:~ REED from SILVERPRINT Ltd.Agents - "NEW" Japanese "SEJ\GULL Paper

'The "ALl..-IN" ticket price at the .A&H Group anrual CCNFEROCE includes a fine saturday night dinner ,with selected french wines.

'The Crystal Palace meals are fisrt class am the equal of most hotel meals.

'00 views of the Saturday tables,pictures by Brian Tremain FRPS.

A team of expert photographers urrler Brian at the British ltlseum, volounteered their free tine to ''PRESENr" a great deal of the ''W)RI<SHJP" to delegates this year. Thank IDT gardner & Parry,D.'W.'.>rrel.A.Cooke B. Wisden. J .~11. V .Croucher. K.Malone & K.Maclxmnell.In fact all that helped Victor µ.it on this Gram Teclmical Conference.