Lance, Under certain conditions there can be a slight colour cast, e.g. photographs in the shade at midday in summer may have a slight blue cast; similarly in the mountains and with snow. The light from the deep blue sky is less absorbed by the atmosphere when the sun is directly above and is very blue, giving rise to this blue cast. Towards the beginning and end of the day the light is warmer, as more of the blue light is absorbed by the greater distance the sunlight travels through the atmosphere (the sun being lower in the sky), giving an red/orange cast. When using colour negative film, most casts are filtered out when the print is made (professional processing labs have this down to a fine art); fluorescent lights give a greenish cast and this is more difficult to remove. Even daylight film, recorded under incandescent light can be almost corrected to give all but a warm glow. If you take a lovely sunset on negative film, often the lab will correct this to give a 'white' sky and it will be nothing like the original scene. Very disappointing. They should know that the photographer wanted to record the vibrant red and orange glow in the sky. ;-) However, transparency film is the end result and so whatever the colour temperature is, this is recorded on the film. If severely different from, say daylight film's recommended 5700/6000K, it will have a cast. Above this figure gives a blue cast and below, a reddish cast. Incandescent lights give a orange/yellow cast, having a 'warmer' but lower numbered temperature. In this situation you require a blue filter when using daylight film (I cannot remember the Kodak Wratten filter numbers off hand). The larger the 'K' (Kelvin) number, the 'cooler' the temperature. A clear blue sky can be upwards of 40,000K and a candle just a few hundred K. The reason why correction from the blue sky is not required for midday sunlit photographs is because the proportion of warmer sunlight is far greater than the influence from the colder blue sky. In the shade there is no direct sunlight, the light just coming from the cooler blue sky. Similarly when using electronic flash indoors. The flash light will have more influence than the incandescent light bulbs, so no correction will be necessary (unless a time exposure is used which will reverse the proportions of lighting influence). =20 With transparency film it's WYSIWYG. So, one advantage is that the lovely sunset is recorded as a red sky, just what you want. However, the blue cast in shade at midday or in the mountains can give a somewhat cool feel but this can be corrected with a rose tinted 'warm-up' filter. Professional photographers may be required to photograph products with 100% colour accuracy, so will use a colour temperature meter and be able to use the correct filtration to adjust the lighting to accurately match the film. For 'normal' photography with daylight transparency film a 'warm-up' filter is really all that is needed unless you are indoors with incandescent lighting. If you want to record accurate nature colours for instance, then more accurate filtration will be required. Reference to charts which are based on the sun's elevation (time of day) and declination (according to time of year) and height and source of light have been outmoded by the colour temperature meter. I saw a Gossen meter on Ebay a couple of years ago and thought it would be nice to have. Expecting it to go for a silly price I only looked at it again once the auction had finished. It sold for about $60. A bargain sorely missed. I don't suppose I would have ever used it though but it would have been a nice ornament. ;-) Best wishes John -----Original Message----- From: rollei_list-bounce@xxxxxxxxxxxxx [mailto:rollei_list-bounce@xxxxxxxxxxxxx] On Behalf Of Choiliefan@xxxxxxx Sent: 22 February 2008 14:46 To: rollei_list@xxxxxxxxxxxxx Subject: [rollei_list] Re: Slide film is still alive =20 Carlos, I've been shooting slide film lately and have scanned a few images successfully but not posted anything Rollei related yet. I'm still confused about filtration in shade with slide vs positive film and have another experimental roll to drop off today. So far Ebay has been a great way to buy 120 and 220 film for a fraction of the cost of new stock and the colors are vivid even on the badly outdated stuff. Health, Peace Lance Selma, NC 27576 ~~~~~~~~~~~~~~~~ =20 --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org - Online, searchable archives are available at //www.freelists.org/archives/rollei_list