URL/Contact

Comments

Roger Reynolds

Apr-05.  Advised MBS to contact Barry Senior as lead in the Society on PDI for assessments.

www.midig.org
www.wessex-dig.org.uk
www.rpsdigital-em.org.uk

Regional subgroups of the RPS Digital Group.  Of these, the Wessex site is more comprehensive.  Can also be reached easily via Maureen Albright’s site.

http://ian-bateman.mysite.wanadoo-members.co.uk/rps/frameset-rules.htm

Site by Ian Bateman of Wantage holding detail of the RPS AV Festival in 2006.  AV is a particular form of PDI which has become very popular, especially with new entrants who have not done slide AVs.

Barry Senior

I'm impressed by the list of questions - many happy hours could be spent finding and collating the answers but the problem will always be that the technology moves at a pace and it will be difficult to keep some of the advice current.

The RPS approach has been to keep everything as simple as possible.

We started with a set of images which were viewed and compared as transparencies, prints and by digital projection. This led to the decision that the digital images would be of suitable quality and the work could be assessed.

We have now assessed many hundreds of  images and in practice there have been no real problems. Colour cast problems are very rare. The technical failings, as with digital prints, are over sharpening, poor highlight detail and noise.

The projector is set up using a 21 step grey scale wedge so that the pure white and pure black can be differentiated from the adjacent steps. Colour balance adjustment has not proved to be critical although often the monitor image will appear different to the projected image. The calibration image also has white, black, yellow, green, magenta, cyan, blue and red bars so that a check can be made for gross colour inaccuracies. A set of images, which we keep for the purpose, are then projected as the final check. It is possible to calibrate the projector more rigorously but at a significant cost (>£1K ) for the equipment.

For the Distinctions we require images 1024x768 pixels maximum saved as TIFF files, i.e no compression. This gives a 2.2 MB file for each image. The colour space will be an sRGB colour space. The resolution is determined by the projector which is also 1024x768. The ppi is not relevant once the pixel dimensions are specified. JPEG files will be more convenient for speed of access and projection but some quality may be lost.

Projector technology and performance is progressing so rapidly that the best advice is probably to find a local supplier who will allow projectors to be compared using suitable test images under the appropriate viewing conditions. DLP projector technology is our preference.

The RPS uses ACDsee to project the images in sequence using a slide show feature. For exhibitions and club competitions software will be needed which allows images to be moved easily into different folders after each image is shown. A suitable programme is supplied with the Apple Mac.

Barry

Carol Agar

request via Mary O’Connor (Thames Valley) for any info to be sent to forthcoming distinctions workshop in July.

The workshop was provided with the usual style brochures for participants.  The brochures now include the technical detail for preparing digital images for distinctions.

There was one author with digital.  This was run using the author’s PC, connected to an available HP projector, with no setup done at all.  The on-screen results were vastly better than the real slides which followed.

Leslie Goode (Exhibitions)

Via results letters for the 2007 International Projected Images Competition.

The software used was by DiCentra (Steve Wilbur, Beckenham CC, KCPA).

Reviewing the site for DiCentra. Uses MS.NET framework.