Campaigners have welcomed the decision but called for more action in the future to protect the Capital’s historic buildings. The council cannot force the developers to amend its scheme as it already has planning permission.
Virgin Hotels won planning permission in 2016 to build its development at the India Buildings on Victoria Street and on Cowgate, next to the Central Library.
Councillors have now agreed that Virgin will be asked to use lighter coloured materials to reflect light into the library after an independent report found that daylight levels in part of the library will be adversely impacted by the new hotel, due to open in 2020.
The council has also amended its policy to ensure classrooms and libraries in future must have higher levels of natural light.
Speaking at Wednesday’s Planning Committee, council planning officer David Givan said: “This scheme has planning permission. That planning permission does set out what the building materials are.
“On the elevation facing the Central Library, materials including the bronze coloured metal cladding and sandstone shall be used.
“We’ve already been in discussion with the developer and alerted them to the findings. We have suggested to the developer that they should, when selecting those materials, use those which are on the lighter end of the colour palette so that they will allow as much light to be reflected down into the Central Library as is possible.”
Protesters welcomed the decision but lambasted the council for what they perceives as not looking after libraries.
Campaigner for Let There Be Light Edinburgh, Neil Simpson, said: “The future of the Central Library is in a perilous state as a result of the new-build Virgin Hotel, consented under the last administration, and these really are last ditch efforts to mitigate the resulting reduction in daylight by up to 82 per cent.
“While today’s (3) decision is welcome, we appeal to the committee with new responsibility for the Central Library, Education Children & Families, to be far more proactive and visionary about the future of the library and to give it the attention that the citizens of Edinburgh deserve.
“They need only look as far as Liverpool, Manchester, Glasgow and Dunfermline to find city leaders who understand the importance of rejuvenating their city libraries - all are located in important historic buildings into facilities that are fit for the future and admired from afar.”
The daylight report for the Central Library was commissioned by the council’s Education, Children and Families Committee following concerns by Green Cllr Claire Miller that when planning permission was determined back in 2016, the daylight impacts should have been known.
She said: “The independent assessment of daylight impacts on the Central Library makes clear that these impacts will be significant and should have been fully laid before the planning committee as part of the decision process.
“The Central Library is one of our most-loved public buildings and if it’s to be fully accessible to people with poorer vision and to reduce lighting costs in the future, the hotel looming over it is a problem.
“From where we are now, it’s vital that the hotel developers commit to the kind of improvements that are outlined in the independent report. But the council also needs to be better informed about these impacts in future decisions as well.”
A council spokeswoman said: “Planning permission was granted for this development in 2016. Within the context of that permission, we will continue to work with developers to ensure suitable lighter coloured external materials are chosen that help reflect daylight towards the library.”
A spokesman for Virgin Hotels declined to comment.