<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div><div>And now for something totally different: (with a likely followup by Tony Quinn)</div><div><br></div><div>BBC Viewers in the UK will get to see a 40-year old episode of "Dad's Army" in color this weekend, long after the original 1969 Quad PAL color videotape was wiped after being transferred to a 16mm film copy.</div><div><br></div><div><a href="http://www.guardian.co.uk/technology/2008/dec/11/digital-video-restoration-dad-s-army">http://www.guardian.co.uk/technology/2008/dec/11/digital-video-restoration-dad-s-army</a></div><div><br></div><div>The process uses software to decode the "chroma dot" pattern left in the image by technicians who chose not to use a filter to remove the color information at the time the telerecording" (kinescope in the US) was made.</div><div><br></div><div>It isn't clear whether the monitor used in the BBC tape to film transfer was a color or monochrome monitor. Or whether that makes a difference. The major dependency is whether the chroma dots are in the filmed image, which is the result of telerecording technicians <b><i>not</i><span class="Apple-style-span" style="font-weight: normal; "> using a filter to kill the chroma dots during the tape to film transfer.</span></b></div><br><b>The article reports:</b></div><div><br></div><div>"<span class="Apple-style-span" style="border-collapse: collapse; color: rgb(51, 51, 51); font-family: arial; line-height: 19px; ">Says Insell "I was watching a black and white [originally colour] Jon Pertwee [Doctor Who] episode on UK Gold. On the end titles I could see some red breaking through. 'Where is this coming from?' I thought. 'How is there colour coming out of this black and white film recording?'"</span></div><span class="Apple-style-span" style="border-collapse: collapse; color: rgb(51, 51, 51); font-family: arial; line-height: 19px; "><p style="padding-top: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-left: 0px; border-collapse: collapse; background-repeat: no-repeat; margin-bottom: 13px; padding-right: 0px; "><strong style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; border-collapse: collapse; background-repeat: no-repeat; ">Ghost of colours past<br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; border-collapse: collapse; background-repeat: no-repeat; "></strong><br style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; border-collapse: collapse; background-repeat: no-repeat; ">The colour Insell saw, he would later go on to discover, came from a series of electronic artifacts burnt into the film from when the black and white telerecording was first made - a ghosting of the programme's original colour.</p><p style="padding-top: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-left: 0px; border-collapse: collapse; background-repeat: no-repeat; margin-bottom: 13px; padding-right: 0px; ">Manifesting as a pattern of faint dots across the picture, these 'chroma-dots' are the key to colour recovery, a process which has caught the eye of the BBC (<a href="http://www.guardian.co.uk/technology/2008/mar/06/research.bbc" style="padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; border-collapse: collapse; background-repeat: no-repeat; color: rgb(0, 86, 137); text-decoration: none; ">Putting the colour back into the Doctor's cheeks</a>, March 6).</p><p style="padding-top: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-left: 0px; border-collapse: collapse; background-repeat: no-repeat; margin-bottom: 13px; padding-right: 0px; "><a href="http://www.guardian.co.uk/technology/2008/mar/06/research.bbc">http://www.guardian.co.uk/technology/2008/mar/06/research.bbc</a></p></span><div><span class="Apple-style-span" style="border-collapse: collapse; color: rgb(51, 51, 51); font-family: arial; line-height: 19px; ">The breakthrough for the project, which has led to the rescue of the Dad's Army episode, came with the development of useable software created by award-winning computer programmer Richard Russell. A retired former BBC employee, Russell had previously helped develop the BBC microcomputer in the 1980s.</span>"</div><div><br></div><div><b>The March 6 article describes the process more fully:</b></div><div><br></div><div>"<span class="Apple-style-span" style="border-collapse: collapse; color: rgb(51, 51, 51); font-family: arial; line-height: 19px; ">Telerecordings (as they are known) were created by shooting, on 16mm film, a required programme that was showing on a high clarity television monitor. However, there were several problems with the process. Principal among these was the change of the frame rate - from the 50 frames per second of video to the 25 frames per second of film. This can now be corrected by a technique called VIDFire.</span></div><div><font class="Apple-style-span" color="#333333" face="arial"><span class="Apple-style-span" style="border-collapse: collapse; line-height: 19px; "><br></span></font></div><span class="Apple-style-span" style="border-collapse: collapse; color: rgb(51, 51, 51); font-family: arial; line-height: 19px; "><p style="padding-top: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-left: 0px; border-collapse: collapse; background-repeat: no-repeat; margin-bottom: 13px; padding-right: 0px; ">However, there is a more relevant problem. Any black and white telerecording of a colour programme is prone to pick up interference from the colour encoded video signal. This manifests itself as a pattern of small grey dots, called chroma-dots, across the picture. There was a way to stop this from happening, by using a special filter to cut out the electronic artefacts. However, the interference was often deemed so minor that the technicians doing the transfers used no filter and so the resultant film prints often contain a burnt in pattern of these chromadots.</p><p style="padding-top: 0px; padding-bottom: 0px; padding-left: 0px; margin-top: 0px; margin-right: 0px; margin-left: 0px; border-collapse: collapse; background-repeat: no-repeat; margin-bottom: 13px; padding-right: 0px; ">Insell suggested that it might be possible to decode the original colour signal of the show from these chromadots, since they contain an electronic remnant of the original video signal. Since then, Insell has set up an independent group - outside the BBC - to put together a technology to extract this coded pattern within the black and white film and decode it.</p></span><div><span class="Apple-style-span" style="border-collapse: collapse; color: rgb(51, 51, 51); font-family: arial; line-height: 19px; ">"There are various provisos," Insell says. "The quality of the film has got to be good enough to have captured this pattern. We're really talking about working from the original negatives and having an HD scan made to get as much information as possible from the film." Insell also stresses that the process would only work on programmes that were originally recorded in colour.</span>"</div><div><br></div><div>This has me wondering whether the "chroma dots" this process uses are the ones often referred to by US engineers as "chroma crawl," visible as a series of dots "crawling" up the screen if you look at an NTSC picture, closely.</div><div><br></div><div>--(Tony Quinn says "Yes" in a post elsewhere)</div><div><br></div><div>In any case, let's hope that the concept or software now in use can be adapted to NTSC images and used to recover color from monochrome Kines. </div><div><br></div><div>I'd opine that actually implementing such a concept will depend on how archives and rights holders can develop a way to make back the cost of doing so—"monetize" the content in today's lingo.</div><div><br></div><div>The technology also might presage a way to recover color from videotapes that were monochrome recordings of color programs... depending on a lot of "ifs."</div></div><div><br></div><div>Ted</div><br><div apple-content-edited="true"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; ">Ted Langdell</span></font></div><div><span class="Apple-style-span" style="font-size: 12px; ">Secretary</span></div><div><br></div></div></div></div></div></body></html>