In this wind and rain, you may not want to leave home so Brian Sutton has created a virtual tour of the Dulwich Picture Gallery for you to enjoy while you sip hot cocoa in your arm chair.
If you want to see the pictures at the Gallery “close up and personal”, you can find details of how to get to the Gallery and opening times etc at the Dulwich Picture Gallery website.
Brian shares some of his virtual tour trade secrets exclusively for Dulwich OnView below:
Why the Gallery?
Dulwich Picture Gallery is a natural for a Virtual Tour – its stunning interiors, its architecture, the wonderful paintings and of course its setting in grounds which provide a restful place for thought and appreciation. Anybody who loves art, style and history will visit the gallery at some point, but, for those further afield, in the meantime the Virtual Tour can perhaps give some impression of the environment and atmosphere of the Gallery. NB in three years’ time the Gallery will no doubt celebrate its 200 years of history as the oldest public art Gallery in England, so plan for a visit!
The scope and scale of the Gallery as an exciting subject for a Virtual Tour presents its own issues. Shots both outside, inside and in darker areas such as the Mausoleum; the mix of natural and artificial lighting inside the gallery; and the need to show enough of the wonderful art work without files sizes so large that the panoramas take forever to download. All this requires a series of small compromises.
How are Virtual Tours constructed? Well, it’s far from “fire and forget”, because although the pictures themselves take only a couple of hours to take, there’s a great deal of post-processing.
Firstly I clean up (“Photoshop”) any glare or untidy spots, which takes much longer to deal with if left until later. Second, I use PC software to “stitch” the three views I take in each location into something that looks like a Mercator projection of the whole 360? scene (both horizontally AND up and down). Thirdly, this 2:1 “equirectangular” image is used by another software package to build a file that can be rendered by your browser as the 360? view you see on the site.
And finally, for the series of panoramas I have to introduce active buttons in them so that you can navigate from one scene to the next (the blue dots you see). I also add a map at the side with the red active buttons so that a) you can navigate from scene to scene that way, but b) also see from the little radar screen which way you are looking! Seeing a Virtual Tour for the first time can be confusing from the navigation – er- viewpoint, and I think the map helps.
All this post processing takes about two days for a large Tour such as the Gallery – a lot longer than shooting the pictures. But if those pictures are of poor quality, it’s all a waste of time, so it’s important to apply some basic photographic good practice.
These days, digital photography helps a lot to assure that what you see is what you hope to get! That’s not so simple for panoramas, though, because the several pictures taken at each location are stitched together later and if the work isn’t done correctly, they won’t join up properly – either a jump in edges or lines that cross the picture boundary, or worst of all, an empty gap between them.
So, although the Nikon fisheye lens I use has, unbelievably, a 183? field of view – yes, it looks just a little bit backwards! – and so theoretically I could make do with two shots at each location, 180? apart, with a 6? overlap, I always take three shots at 120? apart which gives the stitching software a lot of common areas (66? overlap) between each view to find matching pixels. Flash photography is no good, although since I use a tripod with a camera rotator anyway, this isn’t a problem. What one does have to remember is to take the pictures in manual exposure mode, so that each of the pictures to be joined is at the SAME exposure – automatic exposure would change this since the subject areas vary in brightness, leading to abrupt changes of lighting in the panorama.
In the Gallery, with such wonderful pictures on show, it’s important to avoid reflections where possible, although the open and well-lit ceilings make this difficult. It’s also easy to introduce ghosts, twins or triplets into the pictures, as people move around and might be included more than once, or once in one overlapping section but not in the other. Those of us old enough have all raced from one end of the school photo opportunity to the other to get in twice – haven’t we?!
In the final rendering of the pictures, which are taken at high resolution, I have to reduce that down to about 250k for each one (remember it’s a complete globe in effect so this isn’t really much for the size of the scene) to assure reasonable download times, which does introduce some pixilation when you zoom the panoramas. These days, with Broadband, we are seeing more and more video on the Internet that these high speeds allow, and I’m sure we’ll increase the Virtual Tour resolutions later to take advantage of higher speeds. Talking of video, I think we’ll find that both video and Virtual Tours will continue to have a place; video for the live excitement and story thread, and Virtual Tours to allow the viewer to move at their own speed in their own chosen order through a number of navigable scenes.
Following this Virtual Tour (and the one of Dulwich Park also available here at http://www.briansutton.net/dov) I look forward to re-acquainting myself further with the Dulwich College Chapel where I was married. So watch this space for a Virtual Tour of Christ’s Chapel of Alleyn’s College of God’s Gift, Dulwich – God and weather permitting!